(Like most things I write now, this came about after I read an SSC post.)
What if sexuality really was a choice?
When you turn 13 the sexuality fairy knocks on your door, and you get to choose: How would you like your attractions to be distributed across the space of possible people? Would you like to be attracted to some subset of the people in the “male” cluster of the binomial distribution of gender, or the “female” cluster, or mostly in-between, or neither, or mostly one but sometimes the other depending on the phase of the moon?
In this world, Lady Gaga writes a song called “Chose This Way”. Maybe social conservatives talk about how predilection towards choosing nonstandard sexualities is a defect you’re born with, not a choice, and people need to be rescued from these horrible sexualities they’re inflicting on themselves.
The point is, nothing about the basic ethical rule of “everyone deserves equal rights and respect regardless of who they choose to engage in consensual relationships (of any kind) with” changes. It doesn’t actually have anything to do with whether it’s a trait determined at birth or by the puberty fairy or anything else – there is exactly no reason for society to get in the way or your joyful consensual relationships, and every reason to encourage and celebrate them (to the extent that you’re comfortable with that – I don’t know how you chose when the introversion fairy came to your house, after all).
It looks like the whole idea of “born this way” came about as a defense mechanism against fears that not making nonhetereonormative people miserable could result in more people becoming nonheteronormative. The correct answer is, of course, “so what?”, but that’s a hard sell when you’re trying to get past people’s unconscious flinches and you just really want to visit your partner(s) in the hospital.
The really funny thing is that it looks like, in our reality, genetics account for about one-third of the variance in sexuality. Whatever determines gender and sexuality, it’s probably not a completely static circuit, soldered at birth and left nascent until puberty. There are Complicated Things going on, and I’m willing to bet that the proportion of self-identified nonheteronormative people goes up along with acceptance and tolerance. (That’s an actual offer. If you think that won’t happen, we should discuss terms and pick a judge for our bet.)
So let’s compare this to some other traits: you’re “born with” your sexuality (~35%) less than you’re born with your height (60-90%), IQ (45-85%), conscientiousness (~45%), happiness (~65%), or weight (75-85%) (percentages are best estimates of heritable contribution to variance). And I feel like these are all things where society keeps screaming “You can change this if you believe in yourself! You can be happier, or smarter, or harder working, or in better shape! You can do it! Come on! Why aren’t you trying?!” And pretty much everyone (+/- I-live-in-a-bubble) now recognizes how insane and harmful it is to say these things about sexual orientation, and understands that it’s better to build a society that accommodates a wide variety of orientations and identities than torture people into trying to be something they’re not.
Of course, the true and really-good reason for tolerance is that people’s relationships and feelings should be respected, whether or not the tendencies underlying those relationships were chosen or fell out of the sky. But to the extent that the “born this way” argument makes sense, it makes even more sense for all the other traits that are even-more-heritable. We shouldn’t build a society that is hell for people with low IQs or low conscientiousness, and then comfort ourselves by saying that it’s their fault for being “dumb” or “lazy”. We should be searching for ways to help and accommodate people with low baseline happiness, not just scold them for being “gloomy”. We should be building a world that accommodates people’s sizes, or even better allows people to choose what size they want to be (see Transhumanism is Simplified Humanism).
tldr: Be nice to everyone.