Okay, I have stories with interspecies sex, complete with viable offspring. What kind of gene editing would be needed for that to even work, and how would the resulting child's genes be expressed? And I've ruled that sex between two different species is usually safer than sex between two members of the same species, as long as they have a similar biochemical structure, and thus can exist under the same atmosphere unprotected. And there's no structures or chemicals within their bodies that will cause harm, i.e. a substance inside the human's bodily fluids that would be toxic to the alien, or the alien having spike-lined genitalia. Yes, Ben Ten Alien Force implied human-Pyronite (Heatblast's species) sex, and all I can think is OUCH!

If all the conditions are met, it's safer because STIs can't infect a species from a planet that they didn't evolve on (unless they become asymptomatic carriers), and a lot of genetic modification is needed for a pregnancy to occur (or via some sort of biological material, an nearly-identical genetic code). Or unless space AIDS is evolved/genetically modified, either through accident or by purpose, to infect members of multiple species and immunocompromise them. But with the right two species, interspecies intercourse is 100% safe, unless you get a bit carried away (or get caught). What parent would the baby take after more, and if they had a human parent, with the other parent being an alien that's non-humanoid, whose traits would they take more from?

Would planet of birth be a factor? Like, if they were born on Earth, they would express more of their human side, and if they were born on the alien parent's birth planet, would they express less of their human half? And if an man from an egg-laying species impregnated a human woman, would she lay an egg, or would she develop the baby inside her womb until it grew strong enough to leave? And in the inverse, would the mother give live birth, which is unusual for her species? And would there be a possibility of the baby's genes affecting the mother's genes in a way that gives her traits associated with the father's species? Would they count as their own separate species, a member of two different species, or a bit of both?

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    $\begingroup$ From the amount of questions you have stuffed into a single post it looks like you are asking us to brainstorm with you on a high concept, while we prefer more focused questions. $\endgroup$
    – L.Dutch
    Dec 2, 2020 at 5:48
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    $\begingroup$ What kind of gene editing would be needed to create hybrid alien-human babies with an alien whose genetic code we know nothing about? Are you joking? Questions like this are the poster-children of why most authors don't explain the inner-workings of the science they imply in their stories. VTC:Needs Focus. A lot of focus. And maybe taking the time to carefully read the first two bullets of our help center. $\endgroup$
    – JBH
    Dec 2, 2020 at 6:19
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    $\begingroup$ Interspecies sex with viable offspring is an oxymoron. The inability to viably reproduce is what makes something a different species. $\endgroup$ Dec 2, 2020 at 6:42
  • $\begingroup$ Unless there’s a good amount of sufficiently advanced genetic technology. $\endgroup$ Dec 2, 2020 at 15:46
  • $\begingroup$ I think Presidential Candidate Kanye West had some words to say about this: genius.com/Katy-perry-et-remix-lyrics $\endgroup$ Dec 2, 2020 at 21:02

1 Answer 1


Can't happen not even remotely

Chimpanzees have 98% the same DNA and we can't breed with them. An alien race isn't even likely to have DNA.

Forget weird egg laying aliens from Omicron Persei V. A banana has 60% the same genes so banana man has greater chance

enter image description here

  • $\begingroup$ They would have DNA, if they had the same biochemistry. $\endgroup$ Dec 2, 2020 at 6:29
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    $\begingroup$ @TysonDennis, that depends on how closely you look at biochemistry. Read about chirality. $\endgroup$
    – o.m.
    Dec 2, 2020 at 6:38

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