Assume that in a world with current levels of technology much like our own, a developed country with at least tens of millions of people and more than a city-state sized territory, decided that all active duty military personnel needed to be women. Feel free to pick one (e.g. Canada or France) if you feel this is necessary to provide an answer.

The reason for this isn't terrible important for these purposes - maybe there is a religious or philosophical reason; maybe it is motivated by a traumatic mass-rape experience in a previous war; maybe a highly effective biological weapon that affects only men has been developed - simply accept this as a premise.

Assuming that other military forces in the world remain unchanged, how would this women's only military force be designed differently from existing military forces? How would its strategies and tactics differ?

What military capabilities would be little changed and which ones would be greater or weaker?

Answers need not be comprehensive. Selected observations responsive to these questions would be appreciated.

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    $\begingroup$ Why should they differ in any way? $\endgroup$
    – dot_Sp0T
    Commented May 24, 2017 at 15:45
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    $\begingroup$ @dot_Sp0T If you can articulate a reason why they would not, this would be an acceptable answer. Given that there are no historical examples of such a military, however, and only one legendary one (the Amazons) which involved a very different technology level, this isn't a foregone conclusion one way or the other. $\endgroup$
    – ohwilleke
    Commented May 24, 2017 at 15:47
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    $\begingroup$ @ohwilleke there IS a real world example. As far as I know, the Rojavan YPJ military group is composed entirely by women, and according to wikipedia it amounts to more than 20000 units. $\endgroup$
    – BgrWorker
    Commented May 25, 2017 at 7:43
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    $\begingroup$ If you're going to vote to close a question, make sure to leave a comment explaining why. I cannot for the life of me understand why people think this question is primarily opinion-based. It could be tagged hard-science and get valid answers with the amount of research that has been poured into gender differences. I could potentially understand too broad but not primarily opinion-based. $\endgroup$
    – Azuaron
    Commented May 25, 2017 at 18:10
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    $\begingroup$ After reading this entire page I am incredibly surprised at how little intelligent men think of women. I read comments about how women are weaker, slower, have less stamina stated as if were fact without any proof to back it up. And no statements of them being intelligent enough to be military leaders. Bottom line: the ONLY difference between men and women is we're muscularly stronger and on average taller. Modern warfare does not have anything to do with that since we are no longer swinging swords. A woman can shoot a gun, drive a tank, fly a jet fighter, and guide a missle as well as a man. $\endgroup$
    – Len
    Commented Feb 8, 2018 at 6:54

16 Answers 16


How would an all female military be different? It wouldn't.

Over the last few decades female participation in the world's armed forces has increased markedly. While initially allocated to supporting roles, some have sought to integrate them into combat roles and even special forces. Recently Norway created the Hunter Troop (female special forces team), and the US Army Rangers accepted its first female recruits. Not to mention Yazidi and Kurdish women volunteering with the Peshmerga to get revenge on ISIL and protect their families.

What's interesting to note however is how the debate is different between the Anglosphere and Israel. In the former it is often said that the decision to allow more women into the military, and specifically combat roles, is an imposition by idealistic political masters.

One senior British officer went so far as saying that allowing women into British Army combat roles was: "foolish move" which would be "paid for in blood" and was by "politicians desperate to seem progressive, feminist zealots, and ideologues hell bent on opportunity without exception".

On the other hand... worth noting that US Generals are calling obesity a threat to national security. Clearly when a third of young Americas are too fat to fight, the question of women's eligibility for combat roles is put in realistic perspective.

Meanwhile in Israel the situation is different. Israel relies upon conscription, and so 65% of Israeli women have served in the military. All women are conscripted, but of those 25% opt out for religious reasons, and 10% are not fit to serve. In 2011 33% of all IDF soldiers and 51% of officers were women.

In 2007 the Segev Committee report was commissioned by Major General Elazar Stern, Head of Manpower Directorate. The report recommended opening all military roles to women. It was given to the IDF General Staff, receiving the blessing of the then Chief-of-Staff. It concluded that length of service and promotion had been based mostly on gender, and that:

"This is an archaic model that causes under-utilization of the resources ... of half of Israeli society, and closes off many opportunities, both during service and for integrating into society after service"

One of the reason's the Segev Committee's findings were not implemented in full was due to political pressure from religious authorities. There's more detail worth reading in a 2020 article by The Israeli Democracy Institute: 'Women's Service in the IDF: Between a 'People's Army' and Gender Equality'. In 2009 Chief of Staff Gabi Ashkenazi issued a statement:

In his statement, Chief of Staff Ashkenazi listed three motives for integrating women on an equal footing as men into the IDF: 1) Women must serve in the army because the IDF is a people’s army; 2) As a people’s army, the IDF is committed to the principle to the integration of women; 3) Women are integrated into the IDF as part of operational requirements that are vital for keeping the army strong and professional.

Perhaps the problem isn't that women in combat is a bad idea, or that there is evidence against it, but that the USA and UK are spoilt. They've never needed to deploy their entire population to fight for their survival like Israel has.

Modern warfare is far removed from the melee of the medieval era which relied upon tall strong men. There are simply more important factors these days, and just because the enemy may be on average larger doesn't guarantee them victory in melee. Especially since many martial arts allow one to use the attacker's size against them. In a straight up fight where all else is equal, then size will determine victory. But to assume equality in that case is unwise; military standards and efficiency vary considerably. Each army and battle will be different.

It's also worth remembering that the average Vietnamese man is as tall as the average American woman. Was physical size or strength the biggest factor in the Vietnam War?

Weapons and tactics have evolved to minimise risks and allow soldiers to use firearms in close quarters if need be. In the second world war battle rifles were often huge unwieldy things. Not so nowadays with SMGs and the like; ideal for urban warfare. Ultimately technology has allowed us to create physical distance with the enemy, and that diminishes any bonus men have for being big and strong. Does it matter if a pilot is a man or woman? A driver? A sniper? How much of modern warfare is melee, and how many times is this the turning point in a war?

At the very least, a female army is unlikely to be anywhere near as prolific a sexual offender as the Red Army was during the fight to Berlin. In 2007 the UN deployed a unit of Indian women in Liberia as peacekeepers. One concern was that units of male soldiers would be regarded with suspicion by populations which had been terrorised by sexual violence during the conflict. The deployment was considered a great success.

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    $\begingroup$ Selected based on good sourcing of points made. $\endgroup$
    – ohwilleke
    Commented May 29, 2017 at 15:33
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    $\begingroup$ You linked to en.wikipedia.org/wiki/Women_in_the_Israel_Defense_Forces but didn't read between the lines. It looks like most IDF women are in non-combat roles and those that are are mostly in a few battalions $\endgroup$
    – RonJohn
    Commented Mar 15, 2018 at 3:14
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    $\begingroup$ Sorry, but the central point of that answer - that strength is unimportant - simply isn't true. Just consider the loads carried by coalition forces in Afghanistan - not to mention the need to carry each other. I have no issue with women in combat units, but it should be realised that very few are physically up to the task (indeed, not that many men are up to the task either). $\endgroup$ Commented Jun 22, 2020 at 17:27
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    $\begingroup$ While the IDF offers an interesting example. There is a lot more going on there. Israel does not actually fight for survival, the scales of power is absurdly in there favor. No tanks or aircraft engagements afaik for example. And since 1973 no actual war against a state. They are a small country and are NOT expected to EVER fight any large state. The UK or the USA on the other hand? They might need to fight China or India or Russia or Germany or Turkey or Japan or the largest countries or even alliances out there. So the overall creed of the large nation is not in anyway the same. $\endgroup$
    – Seallussus
    Commented Jun 23, 2020 at 20:01
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    $\begingroup$ @DrMcCleod I'm sure you can write a better one with more citations then. $\endgroup$
    – user20787
    Commented Jun 24, 2020 at 12:12

Immediate Effects

The first thing the new military will have to deal with is the enormous loss of military experience at all levels.

Going by US numbers, you've just lost around 85% of your people. The balance between enlisted personnel and officer ranks is roughly equal, but the loss is worst at the highest levels of the officer corps, where you've lost 93% of your institutional experience, as well as nearly ALL of your front-line combat experience. The people who've been out there, making mistakes and learning from them for years, are suddenly gone, and unable to pass those lessons on to the next generation.

The effect is going to be a lot like the infamous Red Army Purge conducted by Stalin; exactly how that affected Soviet performance in the early part of the Great Patriotic War is still being debated, but it's generally agreed that the inexperience of the commanders and officers contributed a lot to their early defeats by the Germans.

To cope with this, one can imagine a need to recruit very aggressively, and promote rapidly, as well as a focus on education for high-ranked officers. Sun-Tzu, Vegetius, and other classics are going to become bestsellers, as are other war memoirs. With any luck, the all-female force will have a chance to get some combat experience in skirmishes or peacekeeping missions before they need to fight for their lives.


Biologically speaking, women on average are not as strong as men. This is just a fact. Training and exercise can overcome a woman's naturally lower strength, but she'll need to train longer and harder than a man to get the same results. In any kind of physical fight, the female force is going to be at an overall disadvantage, whether it's fought with rifles or bayonets.

The army should therefore institute very strict daily PT requirements for their infantry, and weed out anyone who can't meet them. They're basically going to be the British Army on steroids - a small infantry force, but all dedicated, highly trained professionals.

Since it's going to be harder to maintain infantry, a greater emphasis on battlefield mobility, infantry fighting vehicles, armoured transports, and armour is very likely. That in turn is going to lead to a very strong emphasis on logistics.

You're going to end up with a relatively small, highly trained, highly disciplined, professional force. They'll use a lot of armoured vehicles, but they'll be inexperienced at first, and will need to be constantly training and learning. An environment where a soldier can speak frankly to her superiors will be essential, as will promotion by merit.


So, you've got a small army. Not the end of the world. Your best bet will be short, sharp action, bringing concentrated force to bear on individual enemy elements. Most of the heavy fighting should be conducted by armoured vehicles like main battle tanks, light tanks/armoured fighting vehicles, air power, etc.

Your infantry forces would be a reactive force, able to move quickly to trouble spots as needed with less difficulty than the main armoured units, and able to perform the many tasks needed of the infantry in a modern war, like building clearance. Each infantry squad would have its own attached Infantry Fighting Vehicle to transport them quickly to trouble spots and provide fire support. The soldiers would deploy from the IFV, use it as cover, and return to it when they were needed elsewhere.

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    $\begingroup$ There is also likely a huge social/political aspect of sending wives and daughters into battle that would probably influence how politicians chose to use the military. $\endgroup$
    – StrongBad
    Commented May 24, 2017 at 20:26
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    $\begingroup$ Not if those wives and daughters are widows and orphans. $\endgroup$
    – Rick Ryker
    Commented May 24, 2017 at 20:31
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    $\begingroup$ We're assuming a culture that has already decided to go 100% female army. I don't think we can really make any sort of reliable assumptions about the social/political implications. $\endgroup$
    – Ben Barden
    Commented May 24, 2017 at 20:39
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    $\begingroup$ Physical strength has little use in a modern army, only a few functions still require it. $\endgroup$
    – Sasha
    Commented May 24, 2017 at 22:46
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    $\begingroup$ Between body armor, weapons, ammunition, and other gear, modern US soldiers routinely carry 60-100 pounds of gear. Most healthy adults can lift that much, but carrying it around all day requires a LOT of energy. It would be, proportionately speaking, a much larger percentage of an average woman's weight which would magnify the effect. This army would likely change the nature and length of its missions to lessen the load each individual carried. But to say physical strength doesn't matter to a modern army is not true. Edit: I see this is discussed in more detail in an answer below. $\endgroup$
    – Joe
    Commented May 24, 2017 at 23:07

The answers vary on different timescales.

1 Year

On the one year timescale, your military is going to be dramatically weakened by switching to all women. This is a simple cause and effect relationship. If you suddenly fire about 85% of your employees, and then hire a bunch of new employees, you're going to have a massive brain drain that will hurt, regardless of whether or not these new hires are done along gender lines or not. You will also find you have to lower your standards because there's not going to be a massive body of women who are ready to take on this role. You can only employee so many people on a national scale before you drain the talent pool. This happened post 9/11 with the intelligence agencies, who suddenly demanded a massive number of additional IT personel. The security experts warned that they were trying to hire more people than the talent pool would permit, and they would get lower quality personel as a result. Snowden was one of these new hires from that timeframe.

Other than this, nothing would change on the 1 year timescale. All tactics, strategies, etc. will remain the same. Militaries move slowly. It can take them decades to bring in new technology, long after the commercial culture has adopted them ubiquitously. This, of course, is also a very rational process: their lives literally depend on their stuff working in extreme climates with an enemy military actively trying to break them and end their lives. They would use the tried and true approaches instead.

10 year

In the 10-30yr region, it gets a bit more interesting. This is enough time to really properly train up new talent, and start thinking about a steady state pool of soldiers. This is where I would expect to see the first gender specific adaptations, and I would expect to see them fall along the lines of the typical gender stereotypes. I make this assumption because on this timescale, society hasn't had any time to adapt the gender roles we raise our children to in response to this change in the military. You're still going to have people raised in the same manner. More importantly, the higher up the chain of command, the more traditional people will be because they're the older generation.

I expect to see tactics change to work around lower physical loads but leveraging the differences in how the masculine and feminine mind work. Combat will be directed to where attention to millions of tiny details and multitasking will be more important, because those are things that stereotypically the men in the opposing army aren't so good at. Rule number 1 of combat is to know thyself and know thy enemy -- make the battlefield inhospitable for them, and friendly for you. I would expect to see more fluid approaches in the highest levels of strategy, and fewer directed approaches.

100 year

This is where it gets really interesting. On the timescale of 100 or 200 years, you have substantial time to adjust the gender roles over multiple generations. This, in my opinion, is the open question that is explored by those who push gender limits. Just how much of our gender roles are actually tied to real life practical limits of the sexes versus how much is the culture that we have built around these limits to make them disappear. Its entirely possible that we find women actually aren't the best suiteded for warfare, and we go back to using men. It's entirely possible to find that the physical differences between them matter little compared to the mental effects of gender roles, and a change in gender roles could make women completely suited for warfare. Its also entirely possible that we might find out that some of our gender roles actually affect hormones enough to undo any sex specific physical advantages men have. We really don't know the answers on these timescales. Psychologists and biologists are still actively theorizing here.

100 years is, however, enough time to completely overhaul the tactics of the military. In fact, all militaries will have overhauled their tactics and strategies on this timeframe. 100 years of technical advances is more than enough to make entire military theories obsolete.

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    $\begingroup$ One could argue that the prevalence of men-as-warriors throughout human history is the ultimate case study of the influence of gender on combat ability. $\endgroup$
    – PipperChip
    Commented May 24, 2017 at 19:44
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    $\begingroup$ @PipperChip I think you are probably right. We only have a few million years of evolution behind it, although with the shift to more and more technologically empowered ways of waging war, it's not as obvious whether that case study is relevant today. However, we do have to remember that the OPs question intentionally handwaves the reason for the shift to female combatants. The rationale behind that might be a valid argument for why the old ways no longer apply. $\endgroup$
    – Cort Ammon
    Commented May 24, 2017 at 20:26
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    $\begingroup$ @PipperChip The problem is that there's a reproductive advantage to letting men die in war (instead of women): one man can impregnate several women at a time, a single woman cannot have children from multiple men at the same time. This clear evolutionary advantage in who is allowed to die could easily be masking the combat effectiveness differences (if any) between the genders. Beyond that, warfare has changed faster than people have evolved, so who's to say which gender is more effective at modern warfare since a mass-scale female army with modern weaponry has never existed? $\endgroup$
    – Azuaron
    Commented May 25, 2017 at 13:46
  • $\begingroup$ The OP asked for how a women only military would be different not for a discussion on why men are better at it than women. It is presumed that whatever happened happened already and they dealt with it by going to an all female army. Imagine a world were a genetic aberration entered the population which was expressed in men only on their x chromosome and which spread throughout the country's population in a single generation making too difficult to undo. Further image that his genetic aberration caused all men to die by the age of 17 with a standard deviation of 2 years. 98% between 13 and 21. $\endgroup$
    – Rick Ryker
    Commented May 27, 2017 at 5:49
  • $\begingroup$ @RickRyker In that scenario, see my answer for what would likely happen on the 1 and 10 year timescales. On the 100 year timescale, it's not very clear, as my answer pointed out. $\endgroup$
    – Cort Ammon
    Commented May 27, 2017 at 20:57

Physical Strength and Endurance

During the Cold War, many countries drafted young men to serve in the armed forces, and later in the reserves. Some were fit, some were less fit, most were able to serve in some capacity.

These days the armed forces are much smaller. A medium-sized country should be able to find a hundred thousand women who are as strong and fit as the average 18-year-old couch potato. Questions of strength will hurt in some roles, like hauling mortar bombs or hand-to-hand combat, but look at the kind of people who got drafted into the infantry as WWII ground on.

Social/Psychological Factors

These are a bit tricky because they might no longer apply as we know them when a country is prepared to go for an all-female army.

  • One could argue that young men make good enlisted soldiers because they will take stupid risks to impress each other and any females who may be watching. When push comes to shove, soldiers don't die for an abstract ideal, they die to avoid disappointing their comrades. Would the same dynamics develop in a female army? Will they be less macho and more nurturing? Will that make them better or worse soldiers?
  • I'm assuming that the other countries will not change over. How will a male infantry squad react if they are told to storm a bunker held by female soldiers? Chivalry on the one hand and sexual violence on the other hand have always been part of warfare to differing degrees. They were never completely absent.
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    $\begingroup$ The issue with other armies not wanting to fight women is real. ISIS is having trouble combatting an all woman platoon that's being fielded against them. Somehow, within the ISIS ranks, the rumor got spread that if you get killed by a woman in combat, you dont' get to go to heaven. This rumor has done serious damage to morale when facing these women. $\endgroup$
    – Cort Ammon
    Commented May 24, 2017 at 17:39
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    $\begingroup$ "One could argue that young men make good enlisted soldiers because they will take stupid risks" one could more easily argue that that's why they would make worse enlisted soldiers. Battles are rarely won by taking stupid risks. More often they're won through thoughtful tactics and disciplined soldiers. $\endgroup$
    – apaul
    Commented May 25, 2017 at 0:26
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    $\begingroup$ @apaul34208, discipline and thoughtful tactics are extremely important for the people making the decisions. Once those decisions are made, a swarm of testosterone-fueled idiots are quite effective at carrying them out. $\endgroup$
    – Mark
    Commented May 25, 2017 at 1:30
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    $\begingroup$ @Mark Just sayin that stupid risks cost lives... In general you should want your soldiers professional and on point. $\endgroup$
    – apaul
    Commented May 25, 2017 at 1:53
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    $\begingroup$ @o.m. the average 18 year old male couch potato still has much more testosterone than an above-average 18 year old woman. That's why PT & CFT levels are significantly lower for women. military.com/military-fitness/marine-corps-fitness-requirements/… $\endgroup$
    – RonJohn
    Commented May 25, 2017 at 12:03

Wow! So many answers without mentioning any of the positives that women bring to the table. To be clear, there are feminine men and masculine women and this answer deals just with the advantages of typical and stereotypical women.


Many answers have claimed without justification that women have less endurance than men. The truth is, women have plenty of endurance for the purposes of military activities. In fact, women hold all of the records for super long distance swimming.

Risk Taking Behaviors

Since women tend to take fewer risks, one would expect said fighting force to more rapidly evolve tactics that involve avoiding stupid risks, much as modern (after 2000) warfare is much less risky than its World War era counterpart.


Military culture has long suffered from toxic masculinity. There are real positives when soldiers obey without question, but creating that outlook is often just a high stakes power struggle. One might expect more good ideas to filter up the ranks in an all-female military.


Smaller soldiers need smaller boots, smaller flak jackets, smaller weapons, smaller meal portions and smaller camp accouterments. The idea that a military wouldn't right-size their equipment for their soldiers is ludicrous. Fewer materials means lower costs, so each soldier will be able to travel just as far or further for a marginally lower logistical cost.

War by Other Means

War is kinetic diplomacy. If a country is more worried about its daughters going into battle than it was about its sons, one would expect the balance between diplomatic, espionage and military spending to find a more intelligent distribution.


Every military has a minority of war fighters and a majority of medical, administrative, logistical and research personnel. There's no reason that soon and recent mothers cannot carry out lower risk tasks during the 18 months per child that a pregnancy takes.

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    $\begingroup$ "There are real positives when soldiers obey without question, but creating that outlook is often just a high stakes power struggle." This seems to be a complete no-sequitur (masculinity does not equal obedience without question - men have been the instigators of a vast number of changes in history), and is also very, very unlikely to be the reason for "command and control" style management in the military. To paraphrase a co-founder of Stack Overflow, soldiers are taught to obey without question so they will run at the enemy in a minefield. If you don't do that, you all die. $\endgroup$
    – Rob Grant
    Commented May 24, 2017 at 21:30
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    $\begingroup$ you should probably add to your risk taking section that women aren't expendable. every generation has a surplus of men, and you can lose 10-20% without effecting birth rates. that is definitely not true of women. $\endgroup$ Commented May 24, 2017 at 23:20
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    $\begingroup$ @RobertGrant Non-sequitur. Thanks for the feedback. It sounds like you think the military's command and control style is because obedience saves lives in war. I basically agree. The gap between us here is whether and how you get people to unquestioning obedience. It's been a long time since an American force charged into a minefield, and I expect the utility of that style of warfare is basically antiquated. If you don't see the masculinity in how we've traditionally gotten to unquestioning obedience, I probably can't convince you. $\endgroup$
    – user121330
    Commented May 24, 2017 at 23:32
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    $\begingroup$ Concerning "War by other means": If both involved countries are more worried about sending in daughters instead of sons, and the second country simply fields men instead of women, then the first country has already a bad start into the war. $\endgroup$
    – arc_lupus
    Commented May 25, 2017 at 11:31
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    $\begingroup$ @user121330 "If you don't see the masculinity in how we've traditionally gotten to unquestioning obedience, I probably can't convince you." Given it's just a random claim you've made, I probably agree. Lots of disobedience and creativity in the history of men, so I don't think it's a built in thing. $\endgroup$
    – Rob Grant
    Commented Jul 2, 2017 at 14:25

Impact of Size Differences

Women over 18 are generally shorter than men of the same age. This can vary significantly by region and ethnicity. In the US and UK, men average about 175 cm or 5 ft 9 in tall, while women average 161.8 cm or 5ft 3.5 in tall. In the People's Republic of China, men average about 167 cm (5ft 6in) while women average 155.8 cm (5ft 1.5 in).

Men are taller on average than women by 5.5 inches in the US/UK and by 4.5 inches in China.

The size of warfighters is a significant factor in the design of vehicles, lodging, and equipment.

Having smaller warfighters would make some things more difficult for manufacturers: for example, consider the height of a truck's running board from the ground; for vehicles with large tires and tall ground clearance, the running board or a ladder attachment may need to be lowered to allow shorter warfighters to reliably embark/disembark the vehicles. Along the same vein, assumptions about soldier carrying capacity when it comes to equipment may need to be adjusted downward.

On the other hand, smaller warfighters means you can reduce the size of the cab or increase the number of troops carried, which could have a cascading effect along the entire transportation supply chain (trucks can carry more troops, ocean-going vessels can carry more trucks).

Of course, within any population there's plenty of deviation from the baseline average. You could decide that the military retains some sort of size/strength standards that military personnel must meet, rendering such concerns immaterial (but introducing a new concern: a smaller recruitment pool).

Impact of Psychological Differences

There are significant psychological differences between men and women on average, but it's unfair to make a sweeping statement about psychological differences between every man and every woman. The differences may stem from any of genetic, hormonal, developmental, and social/cultural pressures.

Research suggests that women are more empathic and more emotional than men in general. (Some research argues that women are simply more emotionally expressive rather than more emotional, so this science is certainly not settled.) It also suggests that they are less likely to display aggression directly.

If women in general are more empathic, a female-directed military may be inclined to avoid conflict and pursue diplomatic solutions, but this relies upon the specific women with decision-making authority having both greater empathic perception than their male counterparts and having some means of applying their empathic perception to their (potentially faceless) enemy. In all likelihood, the impersonal and weighty justifications for engaging in modern war would hold the same sway, regardless of whether it's a man or a woman who makes the decision.

If women in general are more emotional, including greater capacity for both joy and fear, that could also affect decisions to wage war or initiate conflict. But again, the decision to wage war is often made at a state level so the personal feelings or intensity of feelings held by decision makers may not change their ultimate decisions when faced with the same options and consequences.

If women in general are less directly aggressive, this might actually serve to the advantage of their military in modern large scale warfare, where combat is often impersonal, waged by proxy with bullets, rockets, missiles, and drones instead of in close personal combat with fists, bludgeons, and blades. An indirectly aggressive military might be more willing to embrace asymmetrical warfare, including booby-traps, or strategic maneuvers like cutting off enemy supply lines.

But there are two big caveats with trying to predict the psychological behavior of a military based on its gender composition:

  1. Individual members of the military will deviate from the average. In much the same way that the average soldier will be different from the average man, the average female in the military will not necessarily match the psychological profile of the average female outside the military.
  2. Their behavior will necessarily be informed by both their experience and training. Nobody is naturally an ideal soldier or general; the abilities to fight and lead in a war require the suppression of some instincts and the elevation or acquisition of others.

Any innate psychological differences between the sexes might thus prove insignificant compared to the differences between soldiers and non-soldiers.

  • $\begingroup$ Your information about average height is actually is pretty interesting - the difference between, say, Chinese men and US women is about 2.5 inches, which is much less dramatic and calls into question some of the more forceful assertions that the (average) size difference is significant and limiting problem for soldiers... after all, China has an active military force despite the ~3in difference between their men and US or UK men. It may well make a difference in logistics or tactics or gear, but perhaps not the absolute difference others are predicting. $\endgroup$
    – Megha
    Commented Jul 6, 2017 at 4:02
  • $\begingroup$ @Megha Right... and for most militaries, the equipment and vehicles are designed for the warfighters, not the other way around. If equipment sizing mismatches cause inconvenience or otherwise impact mission performance, that just means new or modified equipment is in order; the process of acquiring new equipment and adapting it to the needs of both the warfighter and the combat theater is constantly taking place anyway, regardless of sex. $\endgroup$
    – Thriggle
    Commented Jul 6, 2017 at 14:06
  • $\begingroup$ Note that women right now operate the exact same heavy equipment at mines or construction sites as do men, without any alterations in vehicle design necessary. You'd be hard up explaining why a dump truck capable of hauling 200 tonnes doesn't have to be changed while a truck carrying two and a half tonnrs does. $\endgroup$ Commented Feb 12, 2018 at 3:59
  • $\begingroup$ @KeithMorrison Commercial construction vehicles are designed freely and marketed competitively. Military equipment is designed according to precise contractual obligations. Commercial manufacturers gain a competitive advantage by making their equipment more accessible for more workers. Defense manufacturers worry first about ticking all the boxes specified by the gov't contract, and then about reducing cost or increasing maintainability so that their equipment will be chosen over competitor products. If the contract specified a minimum warfighter size, product designs will reflect the minimum. $\endgroup$
    – Thriggle
    Commented Feb 12, 2018 at 16:47

I'm going to take a different approach than most of the other answers here. Given the current trend in warfare towards hardware and away from large ground forces, I would guess that after the initial transition period, things would carry on in much the same direction that they're already moving.

Modern militaries already prize mental aptitude over physical strength. Your ability to operate the technology is way more valuable than your ability to lift heavy objects... More and more combat is being conducted by drones, air power, heavy vehicles, and war ships. While infantry is still used and is still important, it's very rarely used as a front line. Even when it is, combat is rarely if ever hand to hand, it's much more finger to trigger and infantry weapons tend to get lighter and more efficient with each new generation.

"How would a military staffed only with women be different?"

It wouldn't be much different at all in the long run.

Also... A lot of the answers here also seem to suggest that women are less physically capable as a given. I reject that assumption. While men tend to have more upper body strength, women tend to have greater lower body strength. There isn't really that much difference in muscle mass without physical training, it's just placed differently.

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    $\begingroup$ "While men tend to have more upper body strength, women tend to have greater lower body strength. There isn't really that much difference in muscle mass without physical training, it's just placed differently." DIfference between muscle mass and strength. It's why testosterone is so important, and why female athlete's illegally dope with it. Though, given it's a warfare scenario, there's nothing stopping the gov't overseeing a safe steroid program to help women build themselves up to a stronger-than-normal level while they're in service. $\endgroup$
    – Philbo
    Commented May 25, 2017 at 7:58
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    $\begingroup$ @Philbo: Who needs a "safe" program, when you are in war? $\endgroup$
    – arc_lupus
    Commented May 25, 2017 at 11:32
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    $\begingroup$ @arc_lupus surely after service, these women will still want to have a healthy pregnancy. I can't imagine taking male hormone steroids to the absolute limit of their bodies would be conducive to that...and there's no point winning the war if there's no next generation. $\endgroup$
    – Philbo
    Commented May 26, 2017 at 12:36
  • $\begingroup$ Size, menstruation, and other female biological needs would be factors too. Probably not all that impactful overall, but some adjustments would need to be made. For instance, guns might need to be slightly smaller, but food costs would be smaller too. $\endgroup$
    – Beefster
    Commented Jun 16, 2020 at 21:32

I wanted to give some time for answers to percolate before providing any answer of my own, but I'd make a few observations, to ground the analysis, without really resolving some of the trickiest and most interesting parts of the question.

Lots of a military force involves an Air Force and a Navy in addition to the Army. In 2015 in the U.S. military, the force structure was:

  • Army 491,177
  • Navy 326,504
  • Air Force 312,195
  • Marine Corps 184,587
  • Coast Guard 40,069

Air Force

In the Air Force, very few personnel actually enter the "battlefield" on a plane, about 95% of the personnel supporting each aircraft are ground crews, where issues of physical strength could be addressed with greater use of machines for lifting and applying strength.

The number of pilots in the Air Force is sufficiently small that your recruits can be very gender atypical, e.g. in emotional and personality character, and still easily to secure in sufficient numbers.

Physical strength and size aren't particularly important in pilots, and the crew portions could be adapted in size for women fairly easily.

The Air Force is currently 19.1% female.

A meaningful subset of the Marines are part of its own internal Air Force to which similar considerations would apply.

Navy and Coast Guard

Many positions in the Navy call for sailors who are actually below average relative to men generally in size, especially submarines. And, relatively few positions on a modern ship call for exceptional physical strength that could not be replaced by more intense use of machines to assist in lifting and moving things. If anything, an all female ship or submarine might more easily achieve a cohesive crew on a long deployment than a ship with only men.

Most of the hand to hand combat training in the Navy is directed at sailors maintain order vis-a-vis other crew members who get unruly, and protecting ships that are docked when it is not necessary to carry lots of heavy gear over long distances on foot.

The U.S. Navy is currently 18.1% female, the U.S. Coast Guard is currently 14.8% female.


While some specialties in the Army fit the traditional stereotypes of what a soldier is, many do not. The U.S. Army is currently 14.2% female.

Lots of soldiers in the Army and lots of Marines (which is currently 7.7% female) have jobs like driving supply trucks, providing medical care, maintaining equipment within forward operating bases, feeding the troops, reviewing intelligence from drones and satellites and troops in the field, and so on. In military lingo they are called "Fobbits" because they work in "forward operating bases".

Certainly resources like artillery have become more accurate and have required less crew support over time, requiring fewer personnel to achieve the same military outcomes.

Another role that was traditionally in the front lines and considered to require physical traits associated with men was operating a tank, even though there were maximum personnel size limitations on tanks. But, the number of tanks in the active duty force has declined greatly, because they have become less militarily useful in modern conflicts, and the tanks that remain have become more automated. Many proposals to make tanks even more automated have been rejected because they weren't a priority, but could be adopted in an all female force.

New positions like drone operators also don't have very gendered demands on personnel. Neither do some quite front line positions like helicopter operators.

Certainly, positions like infantry and special forces would be very strongly impacted, and how those posts in the military would change is very notable. But, those positions are a minority of the modern military, and the changes would be far less dramatic than they were in the days when infantry fought with swords rather than firearms.


If one assumes that the Air Force, the Navy, the Coast Guard, and the aircraft operating part of the Marines won't be much different, those components of the military, which make up about half of the U.S. military personnel, wouldn't change very much in character or capabilities.

The Army and Marines would certainly be impacted more, but probably only about 1 in 3 members of those forces would be in the kinds of positions that would be impacted very much. Perhaps up to 250,000 personnel out of almost 1,355,000, or about 18% of the force would have strongly impacted by the transition in how they could or would operate.

Thus, about 82% of the force wouldn't change very much, while about 18% of the force would change a lot in some of the ways discussed in other answers. How that 18% would change is very interesting, but one shouldn't overstate how representative that portion of the force is to the entire military force either.

Transition Period Duration

There would have to be a transition period during which men were phased out of the military and women were phased in, because lots of military skills can only be learned by doing under the supervision of people who know those skills.

But, this wouldn't take terribly long because the military is constantly cycling through personnel. Much of the active duty force serves for four to eight years before returning to civilian life, ten years would be longer than average, and twenty years is about as long as a military career gets.

So, over twelve to sixteen years, a very large part of the transition could be completely relatively seamlessly, without catastrophic loss of skill sets limited to experienced veterans. If there were a greater rush, an eight to ten year transition could still be manageable although it would carry higher costs particularly in the loss of skills at higher ranks where personnel turnover is not as rapid.

  • $\begingroup$ While women could easily take on the role of flying helicopters and larger planes, would they be able to deal with fighter planes? The Air force has that g-force test that involves locking all their muscles out - considering the low number of men fit enough and genetically able to pass that test (it involves contracting a lot of muscles to stop all the blood rushing out of the brain while trying to breathe through a closed glottis through 8Gs), could a woman pass? If not would it mean the country giving up air superiority? $\endgroup$
    – Philbo
    Commented May 25, 2017 at 8:07
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    $\begingroup$ A biased sample returns biased results. Say there are twelve positions available. If you test a thousand men and ten get through, then test fifty women and two get through, you get your twelve with a 5:1 ratio. But if you include the women who drop out for totally irrelevant reasons (like the intra-military rape rate, or the societal deprivation of women encouraged to enter military service) then the twelve could easily become 1:1 or overbalanced in favour of women before even testing equal numbers. $\endgroup$
    – Nij
    Commented May 25, 2017 at 8:39
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    $\begingroup$ @Philbo Have those tests been done on women? Is there evidence that extreme outlier women are more vulnerable to g-forces than extreme outlier men? If so, that would be good to include in an answer. If not, what physiological evidence is there that this is the case? The kind of physical ability involved in a g-force stress is quite different from the kind of physical ability involved in, e.g., carrying 50 kg of gear. $\endgroup$
    – ohwilleke
    Commented May 26, 2017 at 19:19
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    $\begingroup$ @Philbo There is no significant difference in G tolerance between men and women. pubmed.ncbi.nlm.nih.gov/3753357 $\endgroup$
    – John
    Commented Jun 23, 2020 at 19:59

You will be at many disadvantages

Men and women handle trauma differently: According to a report aggregating the outcomes of 290 different studies conducted between 1980 and 2005, the American Psychological Association has determined that men are in their life times more likely to experience trauma than women, but less likely to develop the symptoms of PTSD. Apart from a lower PTSD to trauma rates, men tend to manifest post-traumatic symptoms differently. In general women respond to trauma by increased anxiety whereas men respond by increased aggression. What this means for a solider is that as a female solider is exposed to the horrors of war, their effectiveness as soldiers will quickly wain as anxiety eats away at their desire to fight, but as men are exposed to it, their desire to keep fighting escalates in response to the trauma making veteran men far more effective soldiers than veteran woman.

What this means for you all female army is that you can not achieve the proficiency of a male veteran fighting force. Your woman army may go into the war just as well trained and disciplined as their male counterparts, but as the war drags on, they will find themselves at more and more of a disadvantage as the weight of all the killing and dieing impacts their their psyches differently.


Women generally reach their peak performance at younger ages than men: In many sports, women tend to hit their peak performance at younger ages than men. This means that there are areas where women in the 12-16 year old age may be likely to outperform men in the same age groups. But, if your army waits until women are 18 to start drafting them, then your women are already mostly past their athletic primes whereas men are just starting to hit it.

This may force your military to recruit at younger ages. This means that you have to choose been recruiting for maturity and recruiting for physical capabilities.

Menstruation & birth control: Women of fighting age naturally experiences a menstrual cycle that can be quite dangerous for a solider. The average woman shows a 30% efficiency variance in most of their daily activities based on the time of the month. This means that when you have a woman who can usually perform the same duties as her male counterparts, that for a few days of the month, she will consistently under perform. For a mixed gender military, this may not be a huge deal (everyone has their off days), but female hormones have a way of syncing up so that women who live and work together will tend to share the same menstrual cycle.

In an all woman army, this means that you could have entire platoons or even battalions on the same cycle which would be pretty easy for a foreign intelligence agency to figure out from intercepted logistics reports. A male army could coordinate attacks to avoid your army when they are at their prime, and hit hard when they are at their worst.

Your all female army would need to rely on mandatory birth control to minimize this very major threat, but long term use of birth control can lead to serious medical complications. This puts your female army at another major disadvantage when it comes to maintaining an appropriate force of experienced soldiers.

There is a frequently cited study on this topic done by the USMC several years back that showed that woman are surprisingly bad infantry in some very unexpected ways.

This study demonstrated that units without women in them performed better in 93 of 134 tasks than those not containing any women at all. Three of the metrics that stand out as the most relevant include:

  • Women are twice as likely to be injured during routine exercises.
  • On average, woman are significantly worse marksmen than men regardless of the firearm in question. Even untrained men tend to be more accurate than a trained female solider.
  • Women are slower on the battle field. Especially when handling heavy equipment such as machine guns, anti-armor weapons, etc.


However, this study is also rather flawed... Having Recently done more research into this, there are several caveats that this study failed to take into account which could have significantly skewed the results.

  • At the time of this study, the military did not design women's combat boots. Women have anatomically different feet than men; so, a woman with the same shoe size as a man will still not properly fit into a man's boot. https://www.shewear.com.au/anatomical-differences-men-women-feet/ This means that the footware would have failed to offer proper arch support, and it would have created pressure points that could lead to more injuries.
  • As for marksmanship, there are 2 key variables that skewed this study. 1: the military did not provide female body armor at this time. Male bodyarmor interferes with a woman's range of motion which forces a bad firing posture; so, any drills done in body armor would have disadvantaged the women in the study. 2: the military defines "trained" as basic training which only includes a few weeks of firearm training. Novice female shooters tend to have worse marksmanship than men because the muscles that handle recoil tend to be less developed in women. So while it is true that women with less than 6 months of firearm training tend to underperform, after about 6-12 months of regular firing experience, women will typically catch up to their male counterparts. They tend to catch up on low calbre, weapons with shoulder stocks faster than handguns or high recoil rifles. So your all women army would need to spend longer on firearm proficiency training, but would not be limited in their ability to become good marksmen. At the competitive shooting level, there is no noticeable difference between men and women except on handguns which are the hardest class of weapon to control recoil on.
  • For the third point, absolute strength deficiencies will slow women down with heavy equipment, but my previous statements about the importance of gender specific boots and body armor likely skewed the numbers here as well to appear more significant than it really is.

At this time, the US armed forces now has female body armor and female combat boots, but I do not know of any studies done to re-evaluate female infantry effectiveness with the new gender specific combat gear; so, woman may still have a few physical disadvantages, but it's really hard to know for sure how significant these would be if you were to redesign your training routine around women instead of men.

What this all means for your all female army

Your best bet of winning any war will pivot on winning quickly and leveraging technology to eliminate holes in your combat proficiencies. You will prefer tactics that don't involve seeing your enemy such as artillery and air strikes, and avoid infantry engagements as much as possible. This means that tactical air superiority will probably be the focus of your military doctrine. If your military can not secure the skies decisively, or if you get drawn into a long gorilla warfare situation, your military is much more likely than a predominantly male army to lose the conflict.


As also pointed out in apaul34208's answer, despite the fact that on average there are some physiological difference between men and women, nothing would fundamentally change because of this difference. We need to keep in mind here that most people recruited in the army (males or females) are quite far from their theoretical top fitness level, and it's only at this top level that differences between males and females are readily apparent. Also, we need to consider that the average fitness level of army recruits has been steadily declining, particularly in the US. But despite the fact that the US is the most physically unfit nation of the developed World, the US army is still the most powerful army of the World.

The physical fitness requirements for women are set lower than for men, but this has to do with the drive to get more women recruited into the army. As we can see here, the standards for men are quite low. E.g. a minimum of 49 pushups in 2 minutes with 80 the recommended number is not a lot, my grandfather could do a limitless number of pushups at a fast rate at the age of 80 (with well enough developed arm muscles you'll pass the endurance threshold where you don't need to stop anymore). The cardio-fitness standards are not set to be at a rigorous level either. Take e.g. the 40 minutes time limit for the 5 mile run, that's just over 12 km/h for 40 minutes and that's well below my training speed at which I run every day for more than an hour. In Norway there exists a female only special forces unit, we can read here that the fitness requirements are quite similar to what is required of US males.


Well, it would not have a lot of narrow-minded men running it, which might make a big difference.

Per 'On The Psychology of Military Incompetence' the biggest issue is generally a commander who gets it horribly wrong and then refuses to change their mind in the face of mounting evidence. Given that this is something which all-too--commonly arises from a highly macho culture, female commanders able to have reasoned discussions and see other viewpoints might be far more efficient at arriving at plans which actually work. They might be less likely to wade into massive bloodshed for the sake of looking manly and not losing face.


Health permitting; what physiological concerns regarding menstruation, hygiene, injury and maternity must be taken into account for an all female armed force, are there scenarios that deprive women off the battle field. Modern technology has taken most of the physical strain from combative development. A rifle has a few pounds of trigger pull A missile is fired at the push of a button The question really is do women have the moral and mental fortitude to engage in war and knowingly kill, namely another woman. During the battle of Mogadishu, enemy forces engaging against US troops sent child soldiers, younger than 17 to fight. Would a woman have the fortitude to shoot or bomb a 14 year old whose firing on them?


We are talking about war here.
War is a beast, and a black hole of human nature.

My perspective may be different, and harsh, and more.

If that happened in hundreds or thousands of year ago.
This action just "inspires" enemies to capture as many captives as they can. Think of the Romans abducting foreign tribe females at the beginning of Roman history. I forget the exact event but it is documented in the book Challenge of the West when the author talks about Rome. You just "offered" women in troops.

War is not romance; it is all about killing, rape, slavery and such.

And if it happened nowadays, the situations have changed a lot, so it is unlikely to be a solid statement that such action will yield a lot of difference in combat capability.

But it does not change the nature of war. The black nature of war allows the winner to do whatever they want to losers.

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    $\begingroup$ I imagine the videos coming out from ISIS would be even more horrific if the pilots/soldiers they caught were women. $\endgroup$
    – Philbo
    Commented May 25, 2017 at 8:12
  • $\begingroup$ Welcome to WorldBuilding! If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$
    – Secespitus
    Commented May 25, 2017 at 9:55
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    $\begingroup$ Certainly war is hell. But, firearms and missiles tend to be "equalizers". Physical might mattered immensely in Roman warfare with spears and swords and longbows. It matters letter in 2017. I'm not asserting that physical might is irrelevant. But a woman with an assault rifle and a flak jacket is much more equal of an opponent for a man similarly equipped than a woman with a swords and shield is to a man with a sword and shield. $\endgroup$
    – ohwilleke
    Commented May 26, 2017 at 19:23
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    $\begingroup$ You do realise it was the fact Islamic State militants were taking women as sex slaves which promoted Yazidi women to volunteer to fight? Making your premise somewhat redundant. People fight harder when they have no alternative. If anything this reality could push an all female army to fight harder. I don't see why it'd be otherwise. $\endgroup$
    – user20787
    Commented Jun 30, 2020 at 20:29

In general, I would expect any country which relies on female infantry troops to be several times more likely to be the subject of aggression than one with a traditional, male infantry. Countries without unfriendly neighbors (Australia, France, ...) and without significant internal unrest would be little affected, with more wealthy nations (more mechanized, more high tech) virtually unaffected, and the less wealthy nations requiring some adjustments in the mix of mechanized and unmechanized infantry. Countries with internal unrest would be far more likely to have their governments overthrown. Countries with unfriendly neighbors would have to spend more on their military, if they had enough time. They'd need more troops, and more effective weapons to counteract the low regard the other nations had for their fighting forces. Problem with this answer is the question. It is obviously absurd to think that the cause of the change doesn't matter. Of course it does! The culture the army is recruited/conscripted from matters enormously. Few cultures expect women to be as physical or as aggressive as males. This matters in determining how aggressive unit tactics can be. We can only speculate, without evidence. The fact that no known nation has ever fielded such a force is neither proof of the hypothesis that female force will be 100x as likely to cut and run as a male force but it certainly doesn't support the hypothesis that such a force will be 100x less likely to fold like a house of cards. There may or may not be a significant biological/physiological difference between the way groups of men and of women behave. Jury is out, but I doubt you'd find many people holding the latter pov, while many hold the former. The one key point is that there are a LOT of women between 18 & 26 that are mothers. I believe they will be LESS willing to leave their children, and less willing to risk their lives for a "greater good" than young men of the same age. It's just a guess, but certainly the proportion of the population that qualifies to get into the military would drop precipitously, and I'd guess the military would have to lower its standards to compensate.

  • $\begingroup$ What about a culture that has a very high ratio of women to men (remember we had to field an entire army of women because ... of hand waved reasons ... which most likely result in such a high ratio) where the right to breed with this limited number of men is dependent on the successful completion of a military tour of duty? We have had cultures where the men to women ration was 3:1, so men were allowed to have up to 3 wives but could not marry until they came back from a successful mission, where such missions had an unusually high death rate. $\endgroup$
    – Rick Ryker
    Commented May 24, 2017 at 20:40
  • $\begingroup$ I would not be surprised at all if the change had a real and significant impact, and certainly the premise of the question is not that an all female force would necessarily be militarily superior or even equal. It is safe to assume that the reason for the change isn't because this country thinks that men are inherently worse fighters. But, this said, the magnitude of the change and they way organization and strategy might change to reflect the change, is non-obvious and interesting to explore. $\endgroup$
    – ohwilleke
    Commented May 24, 2017 at 22:43

since women are shorter, slower and weaker than men, they would avoid any confrontation on foot. basically, infantry would be a tiny group of unusually large and exceptionally well trained women.

since women are less expendable than men, trade-offs between risking lives and risking equipment would tend more towards the safety side of the equation at the expense of much larger equipment budgets. although, this has been happening naturally for decades as we have become wealthier. also, the age limits would be raised (both lower and upper) in order to avoid killing off women before they produce baby taxpayers.

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    $\begingroup$ Who said that women were less expendable than men in this culture? If there are almost no men left then those who are left are much less expendable than all the women. When you have a herd of 50 cows and 1 bull which individual is the most expendable? $\endgroup$
    – Rick Ryker
    Commented May 27, 2017 at 5:31
  • $\begingroup$ @RickRyker when answering questions in world building i assume we are talking about normal human biology unless otherwise noted. $\endgroup$ Commented May 30, 2017 at 15:10
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    $\begingroup$ The Vietnamese are notably shorter of stature and less powerful than Americans.. They did pretty well in confrontations on foot. $\endgroup$ Commented Jun 22, 2020 at 15:31
  • $\begingroup$ my answer assumes "all else being equal". i think the vietnamese would not have chosen infantry if they had any other option. unfortunately, all their material resources were obliterated by years of indiscriminate bombing of all civilian and military infrastructure. your comment does however illustrate that my answer was framed from the 1st world perspective (e.g. canada or france). $\endgroup$ Commented Jun 22, 2020 at 18:53
  • $\begingroup$ In most modern countries the military personnel makes up such a small percentage of the population, the reproductive loss will likely be insignificant. $\endgroup$
    – John
    Commented Jun 23, 2020 at 19:52

What do we know about women, What differences are significant, and consistent on average.

Less muscle mass.

Smaller size.

Will any of this affect the military

No, not really The differences are too small to make a significant difference.

You will see some minor changes in standard equipment. But on the whole this difference will be too minor to notice unless you are doing an extremely deep dive into logistics.

Statistically the military may have less of a discipline problem, males on average are more inclined to commit crime.

One weird thing that may come up is that theire may be slightly larger crew compliments on large ships as space is designed with shorter soldiers in mind.

what effect will it have outside of the military.

Generally female healthcare will be better. Many medical studies focused on men simply becasue the military was paying and they cared more about soldiers which tended to be male. So many studies only studied men, which carried into later research, here you will see the reverse. you will not have the large number of side effects women experience with modern medicine, which is mostly due to the lack of studies on women. This differences will be small and may only be noticeable on a statistical level.


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