A while ago a question was asked about the benefits of having sex with an alien and while it brought up some excellent points, there was a problem I had found. That question had made the assumption of plastic forehead aliens, aliens that are practically human, which made me wonder, could you have sex with an alien?

Considering the fact that a alien would, to a human, basically be a super intelligent alien mixed with the obvious note that human and alien reproduction is infinitely unlikely to be the same, I find it hard that not only could one could not have sex with an alien, but they would be unlikely to feel sexual attraction. Is it even possible to have intercourse with an extraterrestrial?

  • 11
    $\begingroup$ Xenophilia is the word your looking for: en.wikipedia.org/wiki/Xenophilia . In short; attraction to the strange or different. So mentally sexual attraction can happen, yes. Physically is a whole 'nother can of worms. $\endgroup$ – Marky Dec 12 '16 at 19:52
  • 7
    $\begingroup$ People have sex with couches and trees, if there is a biological possibility, I don't see what would hold people back. Remember, sex, intimacy and attraction are different things. $\endgroup$ – Möoz Dec 12 '16 at 21:40
  • 3
    $\begingroup$ @Mooz: Now I want to start a Sex SE just to find out how to have sex with my couch. $\endgroup$ – A. I. Breveleri Dec 12 '16 at 23:10
  • 3
    $\begingroup$ If the alien were composed of antimatter, the union would be very short lived, albeit so hot physicists would be needed to estimate the temperature. $\endgroup$ – Catalyst Dec 12 '16 at 23:45
  • 1
    $\begingroup$ Seeing as no one has ever seen an extra-terrestrial, there's no way we can know if it's possible or not. But it seems unlikely that you'd have the Star Trek idea of aliens which are practically the same species, more like being a different race of humans, rather than being completely different creatures. $\endgroup$ – colmde Dec 13 '16 at 8:47

There are people who feel attracted to all kinds of animals. So someone feeling sexually attracted to a life form from outer space is not that far-fetched. Assuming that there are intelligent aliens who are just as perverted as we are, a xeno-sexual relationship is quite conceivable.

How would it work?

Our erogenous zones react to various forms of stimulation. Aliens might have appendages capable of giving us the stimulation we consider pleasurable. They might have erogenous zones on their bodies which feel good when stimulated by us.

If you would like to know what your extraterrestrial lover needs and how they could satisfy you, there is just one way to find out: together.

First of all: communication

There is one prerequisite: You must be able to communicate with each other. If you can not signal each other your desires, needs, intentions and feelings, there is a good chance that one or both of you might end up bored, frustrated, traumatized, injured or even dead. And some of these states might not be desirable for them. Even worse, they might misinterpret your attempts at flirting for hostility. We are exploring the galaxy to make love, not war!

So establish some reliable communication method first. If you can not find a way to communicate, forget about it and try hitting on something else. There are enough other aliens out there longing for some human touch.

But other than communication barriers, your love can conquer all obstacles.


Inform each other about things you need to be careful about, like any body parts which are fragile or orifices which must not be obstructed. You might also want to consult a biochemist to check if any of your bodily excretions might be hazardous to the other. If so, estimate the risk and use appropriate protection.

Finding out what feels good

First communicate to each other what your erogenous zones are and what kind of stimulation feels good on them. Suggest some practices which might give them or you the stimulation you desire and discuss if you both feel comfortable trying it. If it turns out one of you is anatomically incapable of stimulating the other, don't rule out the aid of tools. Before you decide to try something, make sure that you both know how to signal to each other you feel uncomfortable and would like to stop. Respect each others boundaries and don't go further than you consented to. After the act, discuss what you liked or disliked and how it could work better. And most importantly, have fun!

By the way: Other members of the same species might not react to the same stimuli in the same way, so when you switch partners you should repeat the above procedure. When an alien feels attracted to an abomination from space like you, then you can assume that it is quite a sexual deviant. Its other preferences might be just as unusual, even among those who share their weird fetish for opposable thumbs.


Your chance of having any offsprings by fooling around with an alien is practically zero. Human/alien hybrids are just not going to happen. Imagine rubbing your genitalia against a mushroom (which are the reproductive organs of fungi, by the way). How do you estimate your chance to procreate that way? The mushroom at least evolved on the same planet as you did, so the chance is still higher than when doing the same with an alien.

But by squeezing the mushroom against your private parts you might release its spores and spread them around. This might help the fungus to spread. Something similar might happen with your alien friend with benefits if you play around with their sexual organs.

Or maybe they are hermaphrodites capable of self-fertilization. Then your activities might also very well get the alien pregnant.

But even if members of the species are not capable of reproducing with themselves, you still need to be careful if you decide to get intimate with more than one of them (note that you might have trouble telling them apart). When you don't clean yourself properly between them, then you might inadvertendly transfer genetic material from one to the other and get them knocked up with each other. It's the same way bees assist in the polination of flowers on Earth, so this isn't very far-fetched.

So learn how the procreation of their species works, if there is a realistic chance that your activities might result in alien babies and what responsibility they will expect you to take if that happens.

|improve this answer|||||
  • 1
    $\begingroup$ I think that there should be some suggestion that for safety reasons use condom or at best an environmental suit. ;) $\endgroup$ – Shadow1024 Dec 12 '16 at 21:02
  • $\begingroup$ @Shadow1024 Good point. There might be liquids you might not want to swallow. Added a sentence about precautions. $\endgroup$ – Philipp Dec 12 '16 at 21:25
  • $\begingroup$ I like the new headings and ideas. Reminds me of another answer that had several of the specific headings and discussion points you edited in a little while before that. $\endgroup$ – Zxyrra Dec 12 '16 at 23:53
  • $\begingroup$ Animals maybe, but remember, we're all from the same planet - I would imagine it's mostly mammals or whatever the category above that is. coming from the same branch of the evolutionary tree, they have similar equipment and concept of male and female, with a sort of plug-and-socket interface. Your aliens would have to have evolved the same idea (and similar size!), and not, say, the Centauri "six tentacle" system. $\endgroup$ – colmde Dec 13 '16 at 8:43
  • $\begingroup$ I had to join this SE to be able to like this answer... $\endgroup$ – skymningen Dec 13 '16 at 9:58

"Diddling" can be broken down further

Which leads to the answer "it's mostly possible but be careful and do your research please"

Note: From here on out, I'm going to assume you're talking about species that reproduce sexually. If you're describing asexual reproduction, there is no need or even want for the other party to have sex in most circumstances - therefore, the answer would probably be no.

Attraction? Possible

As other answers have pointed out, there is a community for virtually any sexual interest. Assuming your alien species is the same way, there are likely to be some pairings, though unconventional. Attraction can happen.

It's worth noting that some species do not have consensual sex, even on Earth. It is possible (although unlikely) that this alien species reproduces this way. Therefore, it's possible that one party involved in this exchange (human-alien) may not ever give consent.

Communication? Possible

By the time we observe aliens, we will likely have the technology capable of translating their language. Sound waves? Great, we can speak those. Light? Can be recorded and reproduced. Tactile communication? As long as they aren't toxic, sure. This is important if you want consensual pairings.

Stimulus? Possible

Assuming sex "feels good" for your alien species, as it does for many animals on Earth, then there must be something that can be stimulated to do so. Perhaps a human would need a machine to produce those effects - ex. light, magnetism, electricity, extreme heat or cold - or perhaps it would be tactile, something humans can mostly accomplish.

If sex does not feel like anything for your aliens (or the gender involved with humans does not usually give consent) then the motivation behind sex, assuming still that there is consent when a human is involved, could be for profits. That eliminates the stimulation problem.

Reproduction? Statistically impossible

First and foremost, these organisms are probably very different from us genetically. Major differences in genetic code, and in chromosome count, make it so that cross-species reproduction will not work (most of the time) on Earth. If your aliens have a completely different LUCA (last universal common ancestor) there's no telling how different these things will be!

Additionally, there are many speculative replacements for DNA out there - numerous molecules can carry "genetic" information effectively. It might not be a question of different genes or a different chromosome count, but rather XNA instead of DNA.

It's also worth noting that reproduction requires compatible gametes - sperm with eggs, etc. There are other effective ways to make this transfer - alien gametes may not be able to interract with human gametes.

Finally, the idea of cross-species reproduction also assumes that males are diddling with "female" equivalents, and that females are diddling with "male" equivalents. (1) Even if genes and chromosomes are compatible, DNA is present, and gametes are compatible, perhaps the ones that give birth are the "males" - like seahorses - and the females transfer the genes to them. Acts with this species would result in combining sperm with sperm, or eggs with eggs. (2) It's the future; ideas become more liberal as time passes. How many of these acts will be "heterosexual"?

Healthy timeframe? It depends

Metabolisms vary between organisms. Humans are born, see the world, live, and die through generations while single generations of some trees are around. Millions of successive generations of bacteria flourish throughout a human lifespan.

If your aliens have similar metabolisms to us, expect somewhat healthy timespans. If they have longer or shorter - expect complications.

Safe? It depends

See my answer to this question, which addresses the possible effects of alien organisms on Earth crops. The same ideas apply:

There is no reason for diseases to be compatible if they evolve different genetic material, but the toxins they release may harm humans - and vice-versa. Or perhaps the aliens themselves are toxic to humans! It all depends.

|improve this answer|||||

So assuming that the alien has biology that can be manually stimulated, then I don't see why not? The alien biology might not allow for something like PIV sex, but neither do some human configurations.

So if the alien can be stimulated, and has the ability to stimulate the human one way or another, then it doesn't matter, had sex.

For reference the short story Spar (VERY NSFW)

|improve this answer|||||

You need a universal adapter kit.

Before we find aliens, there will probably be whole-body haptic suits and VR, with technology driven my revinue from porn. So, each partner wears a sex suit, but rather than sending commands to the haptics of the partner in the normal way, they are translated into suitable equivalent actions. Likewise the virtual avatar presented of your partner will be anatomically suitable for you.

Without going full VR, you can imagine small specific mechanical adaptors for individual body parts. For example, it may be shaped like this on one end (choosing an example from real Earth life— it might be three-fingered tenticles or a wide plate; very un-Earthly) and a human female shape on the other, with mechanical actuators triggered by the human’s action.

And don’t forget the very bottom of this answer.

|improve this answer|||||

Yes, but would you want to?

The OP doesn't go into detail about the specific details of this alien, so some degree of conjecture will have to be done.

First, humans are sex machines and will have sex with practically anything: humans with dissimilar anatomy, humans with similar anatomy, themselves, animals, holes in a rock, plastic holes, plastic sticks, ice cubes of various shapes, warm apple pie, etc, etc, etc. (No, I'm not linking to any of these.) Given this immense array of human sexual affection, it shouldn't surprise anyone in the least that some horny person got the hots for an alien and wanted to see how far it would go.

Wear a condom

Sex with an alien means that you'll be merging, perhaps for the first time, two complete biospheres with completely different evolutionary histories. While on the one hand, this alien may have an STD that might convey eternal youth on humanity, it might also unleash the Plague Of End-Times. Wear a condom or make them wear a condom.


As long as there's an approximately penis shaped appendage or a penis-sized hole on/in the alien then sex with a human can happen. It may not be comfortable; lubricant of some kind may be required. There's likely to be some degree of biomechanical incompatibility here, so be careful.


Anything can happen here. The universe of possible alien psychology is so large that to answer in any meaningful way will require will speculation.

|improve this answer|||||
  • $\begingroup$ I wouldn't be worried about alien STDs. I'd be worried about corrosive/poisonous bodily fluids. $\endgroup$ – Mark Dec 13 '16 at 4:42

Not the answer you're looking for? Browse other questions tagged or ask your own question.