Really, what a pointless thing to do.
https://www.quora.com/What-is-the-cause-of-homosexuality-in-animals/answer/Donna-Fernstrom?srid=FO6G What is the cause of homosexuality in animals?I highly recommend you read the book ‘Biological Exuberance’ by Bruce Bagemihl. Sexuality evolved to facilitate reproduction, but it didn’t stop there, and reproduction is not the only purpose for sexuality in a great many species, now. Theists are wrong about humans of course (big shocker, there), but that’s an aside. Humans are just animals, like any other.
Life is messy and full of experiments. Because there is no guiding hand behind it, anything can happen - if it’s beneficial, or even simply just NOT too detrimental, it’s likely to be passed on. One thing has proven beneficial in most species - adaptability. Diversity. A broad range of traits ensures that when circumstances change, at least some individuals will have an advantage. But there’s no intelligent oversight to that, so that diversity is really messy. It includes things that may never be beneficial, as well as things that always are. Simply having a huge range of traits is the benefit, itself, because there’s no telling what the world may throw at you next.
Did you know that when a mated pair of male swans nest, they have a higher success rate at rearing their cygnets? It may be because the males are more aggressive at defending their young. The female they duped into laying the eggs doesn’t really lose out, even though she doesn’t get to help rear them - her genes are passed on, all the same. (Yes, gay animals can still reproduce, and often do - that includes humans. Having a preference doesn’t mean you can’t do what you don’t prefer in order to accomplish something needed).
You never can tell what will prove to be an evolutionary advantage.
Now, homosexuality as an orientation is rare in animals - not that common in any species. Among more intelligent vertebrates, strict heterosexuality is also pretty rare… Most animals are bisexual. (Some arguments have been made that so are most humans, which fits the pattern). Non-human animals don’t have any hangups about their sexuality - they just do whatever they feel like doing. And most of the time, that seems to be ‘whoever.’ lol
This is simply a natural result of how sexuality evolved. The prudish notion that animals don’t enjoy sex is frankly stupid. Animals engage in sex because it feels good and sets off lots of nifty reward chemicals in the brain. (Humans aren’t different). Animals engage in homosexual activity because it feels good, and why SHOULDN’T they? Due to the way reproductive systems work, clearing out old sperm periodically aids fertility. Keeping everything in working order for actual reproduction is a great function of non-procreative sex. It’s also a great stress reliever - the drive to mate is powerful in many species, and if they aren’t able to breed, what’s to be done with all that desire? In a lot of species, young bachelor males mate with each other regularly, because the females are all taken by the older, stronger males. That is homosexual behavior that’s virtually ubiquitous in those species, but it’s not homosexuality as an orientation. Technically, they’re bisexual with a preference for the opposite sex, but only humans care about distinctions like that. It’s psychologically healthy for those animals to engage in those behaviors, and when they’re bigger and stronger, they’ll be ready to compete to actually breed.
Really, the cause of homosexuality in animals is, ‘because, why not?’ I think a question with much less certain answers is, ‘why are humans so obsessed with others’ sexual habits?’