What would make human males an inefficient option for spreading alien genes?

Question

An alien species colonizes worlds across the galaxy, expanding its empire and propagating its race. However, it doesn't do this by subjugating the inhabitants through force, as its technology is too primitive to sustain an invasion. When a mothership reaches a planet, it releases spores into the atmosphere and infects the population like a virus. Over the preceding weeks, the spores slowly take over the body of the host, converting victim's DNA into the alien DNA of the species. When the conversion is complete, the human personality has been completely replaced by the alien mind. The creature then propagates its genes throughout the race, its offspring looking and acting human but having the mind and DNA of the alien race. In time, the entire planet will be taken over by the parasitic species, which then moves on to the next world on the motherships path.

The species has the desire to propagates itself as fast as possible to prevent itself from being discovered. It has come across Earth, where it begins its process of converting the human race. The most obvious group to infect would be human males and take advantage of their reproductive organs. The alien virus would be able to spread the alien genes far and wide in the easiest way. A human male produces millions of sperm a day, and can have hundreds or even thousands of children fairly quickly. However, it can only affect the female sex, as it has found the males to be inefficient in spreading itself. The female sex functions as a bottleneck, as they can only have a limited amount of children at once over long periods of time. This slows down the spread of the alien virus, risking its discovery before it can complete the conversion.

What would make the male reproductive system an unsuitable option to fulfill this purpose?

Answer 1

There's a better way

The alien spores are complex haploid cells that (like many microorganisms) are hardened against desiccation and ultraviolet light to survive in the upper atmosphere. When humans and other animals breathe them in, they embed in the lungs. There the spores fuse with the human cells. They regulate the activity of the human cells to prevent immune recognition of alien antigens much like metastatic cancer cells, using mechanisms such as PD-L1. Meanwhile, the alien genes and proteins have their own well-segregated metabolism which absorbs nutrients from the cell (and thereby the body) to duplicate its own nucleus. Though it is not hardened like the form for long-distance transmission, this duplicated nucleus and a bit of cytoplasm it envelops itself with acts as a spore, infecting another cell nearby.

When spores first infect a human cell, they produce a powerful paracrine hormone (perhaps a gas such as ethylene). The hormone self-regulates to prevent massive overproduction when many cells are being infected, so it is present at more or less constant levels. Until every cell in the local area, a few millimeters, is infected - then the level drops. Using this quorum sensing mechanism, the alien cells begin to produce a second hormone (perhaps another gas such as propene) that specifies formation of a special structure on an external or internal surface of the body, such as the skin or lungs, which is a small cone of a few extra human-alien fusion cells with an orifice. The hormone prevents other nearby sites from forming cones, so they are sparsely spaced all over the body. The cones are quite small and not noticeable without microscopic examination. However, they tap into as much nutrition from the body as they can, and use it to produce an endless supply of dry hardened hydrophobic (non-wettable) spores for long distance transmission. These are spread by coughing and casual contact, and can be picked up by the wind and brought high into the atmosphere.

In this way the alien spreads itself throughout many organisms all over the infected planet - any host that its specialized genome has evolved to be able to subvert. Internally, a vast library of antibody-like binding proteins can be found which can be spliced together to make any two proteins in the infected cell interact. Tying host proteins together in patterns of the alien's choosing controls the fused cell and cause changes in its regulatory pathways. The genius of the alien at the cellular level is that its cells are (a) able to experiment with changes and evaluate whether they improve or worsen their control over an infected organism's cells, and (b) they are able to record their results in special regions of DNA labelled with codes that specify the specific species infected at that time. The cells may not be sentient, but they are biologically evolved to be scientists in their own little field of research, namely turning your cells into slaves.

The spores occasionally attempt to infect the same cell. When this happens, they do not fight - they mate. They swap their alien genomes, including the notes they have made about organisms on many planets. One infects the cell and the other moves on at random, a 50% win for each spore. In this way, the alien spore community as a whole can contain a great deal more information than any one cell can hold individually, and keep it in circulation even if a species has killed all of its infected members and hidden itself away for years.

The spores are not released to bodily fluids for two reasons. #1: in general, spores that release to unknown bodily fluids are usually lost. If an organism is fully infected and their "cones" appear on the retina to release spores to vitreous humor, those spores are wasted. #2: the spores have no way to make notes of how effective a particular method of dispersal is. It is not a short term experiment to test changes in cellular conditions - the spore waits for days or months, on a stone path or in the upper atmosphere, in desiccated form. Put together, these things mean that simple natural selection, unaided by the alien spore's peculiar sort of 'intelligence', has prevented them from forming spores anywhere but on a surface exposed to the air.

Answer 2

The aliens have no game. Human women somehow have the uncanny ability to detect their desperation to mate. Protecting the purity of the human race, one rejection at a time.

Answer 3

A human male produces millions of sperm a day, and can have hundreds or even thousands of children fairly quickly.

Yeah, no. For several reasons, the main one among them being that the number of men in the world (especially the modern world) who, without the aid of technology, could realistically get "hundreds or even thousands" of women pregnant would be approximately zero.

First, the biological: the majority of time, sex does not result in a fertilized egg, if for nothing else than hidden ovulation. Based on the evidence, the majority of the time a fertilized egg will not implant, which means repeated sexual acts are needed to ensure a pregnancy (yes, yes, everyone knows someone who was pregnant the very first time, but we're talking average here).

Let's say we're going for a nice round thousand births, ignoring mortality figures. For a woman under 35, the odds are about 15-20% in any given cycle if she's having sex during her fertile period. Since cycles vary in length, let's just call it a month. But fertilization can only take place a few days of that month. Let's call it 5. So, rounded out, if our alien-DNA altered man wants to knock a woman up, and he doesn't know and she's not telling, he has roughly a 1 in 6 chance of having sex with her when she's capable of being fertilized. But then you have to take into account that 15-20% probability of a pregnancy actually resulting.

So what does this mean? Our alien hybrid, randomly having sex with a woman, will at best have (0.1667 * 0.2) about a 3.3% chance of getting her pregnant on a single act. So, for a thousand pregnancies, when 96.7% of the time a woman will not get pregnant, means our Casanovalien needs to have sex roughly 30,000 times. You, ah, see some of the logistical difficulties?

For a bit of reality, the record for most children is Sultan Ismail bin Sharif of Morocco, with approximately 1,171 children. He was born in 1645, became sultan in 1672, and ruled for 55 years until his death in 1727, at the age of 81 or 82. Based on some simulations, it would take 32 years, having sex twice a day, among a harem of 500 with synchonized periods (used in the modelling, whether or not it is real, thus improving the odds significantly) to pull it off. This would be 23,360 times copulating, so in the same ballpark as my estimate.

Now I'm a geologist by education, so 32 years can certainly seem quick, but in regular human terms, not really. And you said "thousands", so yeah. No.

Now the sociological and cultural: Ismail bin Sharif isn't what you'd call a typical, or even an extraordinary, man. What he did wouldn't be considered acceptable these days as the Casanovalien faces another difficulty: women say no, and harems (Kindle Unlimited ebooks to the contrary) are not generally cheerfully accepted. Now, he might try and overlook that, but the more often he does it the more likely he'll wind up in prison or dead, either because of being a rapist or because inevitably pissing off other who isn't so keen on his behaviour.

So, tl;dr, just because a man produces millions of swimmers doesn't mean he can just go around getting hordes of women pregnant cheerfully and easily.

EDIT

Now, for a reason why it might not work at all: one cause of infertility in couples is because of the presence of antisperm antibodies, which obviously treat sperm as pathogens. ASA may develop in women (and men) when their immune system encounters sperm in a non-reproductive setting, so oral or anal sex. Given your proposed spread of spores, what might happen is that women become exposed to the spores through breathing or ingestion, their bodies react accordingly, and they develop antibodies. The modified sperm cells of Casanovalien share antigens with the spores, which the female body reacts to, pumping out antibodies to fight these invaders. A lot of antibodies.

End result? Casanovalien tries to use his wily alien skills to seduce a human woman. As soon as he starts leaking seminal fluid, she has a severe allergic reaction. Pretty much puts a damper on the festivities. And if she doesn't, the fertilized ovum itself may express these alien antigens and so doesn't implant either, being rejected by the uterine walls.

On the other hand, if the spores are targeted at the female, the alien DNA has more control over the process because it controls the environment fertilization takes place in and thus doesn't develop antisperm antibodies. And since the DNA of the mother has been modified already, it doesn't consider the alien DNA in the ovum to be an invader either, so implantation in the uterus can occur normally.

Perhaps the aliens haven't encountered this specific form of internal fertilization and reproduction before: maybe in some other intelligent species fertilization is external. Maybe others don't have the equivalent of a placenta and are ovoviviparous, so the fertilized ova develop as completely isolated from the mother, so implantation isn't needed. Maybe others were simply oviparous, so eggs outside the body. Perhaps others don't have the same sort of immune system mammals (and humans) have, and so on and so forth.

Answer 4

One of the most obvious reasons for the failure of these ambitious plans is social structures dominating human societies. There are very few males who can spread their seed far and wide. Most human societies, modern and historic, limit sexual interactions for both sexes. And while men have more freedom they still cannot impregnate thousands of women easily.

It is also possible that changes in personality due to alien DNA are big and impossible to hide. So, infected men will be noticed and sent to specialised facilities for treatment. If someone notices alien DNA mass-testing might be employed (at least in some countries).

Other reasons can be related to the mechanisms of sexual attraction. These are still not understood well, but it is possible that alien DNA causes some changes that make males unattractive. For example, changes in DNA can result in changes in body odour and human females will start to avoid infected males.

Yet another possibility is that alien DNA disturbs the process of egg fertilisation. For example, if sperm becomes unable to initiate acrosome reaction, fertilisation fails. Many other problems can occur since fertilisation relies on interactions of many proteins in sperm, egg, and surrounding environment. If alien DNA interferes with protein structure or synthesis fertilisation rates may plummet.

Answer 5

A simple option would be that some aspect of the alien mind inhabiting the male human body makes that human male impotent. That would be a significant barrier to the human male spreading their (now) alien genes.

Answer 6

This isn't answering your question, so I apologize, but there's another problem in your invasion plan.

Even if the aliens replaced all the DNA in all of our cells, we would still be us. The cells still need to function and keep up their own metabolisms. So the alien DNA couldn't interfere with any of that. But let's say that it's not removing anything that the cell currently does to stay alive, it's just augmenting it with alien stuff.

There is the problem of neuroanatomy and basic neuron function. Our minds (if you believe that our minds are a product of our brain's configuration, and I do) has far more information in it than DNA can hold. Our entire genome is about 1.5GB. Encoded in there is the ability to make a brain, but not by any stretch of the imagination is there enough to store the configuration of a brain. When we grow and live and learn, we're modifying our brain's structure, especially when we're young. Our DNA can give us some hints, like structures to make walking easy (left foot right foot), but all of that is shaped and refined by our environment.

The amount of information required to describe an adult human brain's "software" (ie. which neurons make which connections to which other neurons, how strong are those connections, what types of neurotransmitters are released, etc) is way more information than the DNA could hold. You would have to rewire the brain altogether independent of rewriting all the DNA to make that brain have a different person in it. So you would need a way of explaining how that happens in a slow or easy or sudden and undetectable way. The aliens would have to know the human brain hardware really well in order to hack our brains that well. And that's assuming the alien's understanding of minds, consciousness, neuroanatomy was astronomically more advanced than ours and could be miniaturized and weaponized into spores.

And if they were that good at making new minds, why both taking over a planet at all? Why not clone themselves into a deer or a lion over and over and attain immortality that way.

It's a leap! You would have your work cut out for you :) good luck!

Answer 7

It's nothing to do with gametes

The Alien Infection isn't based on sperm or eggs. Instead, the infection takes place during pregnancy. The child develops normally, and when they're developed enough, they're infected by the alien rewrite and taken over. It necessarily follows that the mother has to be the one infected in order to play host to this process.

The male's sex-genes aren't significantly involved in the process because the adult human/alien hybrid is effectively human. Their genetics are more or less human with a few extra functions on the X chromosome to develop the infective parts of the alien biology.

These extra functions rely on the human being having XX chromosomes, an XY chromosome simply won't work with the spores (maybe the aliens tailored their infection to some random person they abducted and they happened to pick up a woman instead of a man)

Answer 8

How about, alien DNA is passed only via attaching to human mitochondrial dna and thus passed only from mother to children.

Answer 9

You know who had a lot of kids?

“The greatest happiness is to vanquish your enemies, to chase them before you, to rob them of their wealth, to see those dear to them bathed in tears, to clasp to your bosom their wives and daughters.” ― Genghis Khan

How did he allegedly do it? Why, by eliminating the competition!

This is the flaw in this plan.

Who is going to be there to make sure the child is carried to term, and also not slaughtered by MILF loving horndogs? Right now population of men and women is about equal, so the biggest barrier to any one man doing his duty for the aliens, is the competition, right? And who is the competition? The infected, right? You are not going to die so Eugene "Moist" Pantywhistle can sire the alien horde, are you? Of course not, the aliens are hijacking your procreative urge, man, they are using spores.

No wingmen!

Thin out that foot traffic and then you can get a circuit going, do your rounds, except after the first few chrysalid kids show up, people are going to view this as a horrible venereal disease. Turns men into murderous rapists, and the kids they have are literally inhuman. People won't get infected. People won't conceive. People will abort. People will commit suicide. People will commit infanticide. Every time a strange guy steps outside, he's a target. Every kid is a target. This is brutal, but so is becoming an axolotl tank.

Healthy guys have exactly the same motivation to thin out the herd as the infected, except of course they'll be breeding true, so every kill increases their value. So you have a two part initial remedy. Some places will have access to post coital contraception. Getting pregnant with a real kid gets you off the assembly line.

Genghis knew his business. It's addition by subtraction.

Once that grim work is well begun now the aliens have a logistics problem.

How are the aliens going to stop the brutalized women from killing the wee alien bairns? They aint children! Feed them rat poison! Push them down the stairs! Give em some smokes! Hell, give em some pills!

So what is the actual practical benefit to infecting men?

• Healthy men will try to kill them.
• They'll try to kill each other.
• Women will surely use the crisis to cement reproductive control.
• The Patriarchy will be a thing of the past.
• With the focus on biology, how long before effective reprisals are carried out? You know their whole reproductive cycle, what's stopping us from using OUR biochem weapons?
• Women have agency, and won't just get bred by aliens. This is not a medieval society.

They would be far better served infecting a few people, entering the population, giving no sign of their plans and promising to share the secrets of spaceflight. Pretending they are human, and those kids are going to adventure across the universe. They get the same result without the resistance. All they need is to spore up a few out of the way villages.

Answer 10

A human male produces millions of sperm a day, and can have hundreds or even thousands of children fairly quickly. However, it can only affect the female sex, as it has found the males to be inefficient in spreading itself. The female sex functions as a bottleneck, as they can only have a limited amount of children at once over long periods of time.

This "bottleneck" is your golden opportunity!

What would make the male reproductive system an unsuitable option to fulfill this purpose?

The key is not "to make the male unsuitable," it is to modify the female system to supersede the male system.

Modify the female system to allow simultaneous fertilization of millions of eggs, and create a natural selection process which favors a select group. Then the male's production of millions of sperm becomes irrelevant; the natural selection occurs after fertilization.

A rudimentary form of this exists in real life; namely, the sperm bank. The male's prodigious production of sperm doesn't matter, because a lab tech with a microscope has replaced natural competition and selection.

Answer 11

The major reason is because the aliens do not see homo sapiens as possessing an order of intelligence comparable to theirs. Just like humans would use human armies, not ants or amoebas to colonise other places, aliens probably have never thought about using human males as an effective tool to take over the plant Earth.

And with higher level of intelligence comes deeper expression of conservation and compassion. (Citation Added: https://www.neurologylive.com/view/are-empathy-and-intellect-incompatible) Just like humans would strive to take over rogue human regimes, none set forth to eliminate - but rather make efforts to preserve - the ant kingdoms and tribes that may co-exist with the human world on this planet.

Answer 12

...if the mechanism already relies on taking over the host's DNA and converting him into human-alike alien, then why the need for multi-generational process? Just infect and convert everyone, in one go, thus minimizing the chances of discovery and successful defense.