Originally a comment by Artymorty on The T is not the LGB.

Tatchell’s wrong, of course, about bisexuality.

Sexual orientation is not culture-bound, and it doesn’t change with the political tides. There doesn’t appear to be all that much variation in the amount of same-sex sexual behaviour across times and cultures (despite what the artsy elites of ancient Greece and Rome wanted us to believe). There are two instinctual factors in sexual behavour: sexual attraction and sexual aversion, and both are almost universally polarized along the sex axis.

The vast majority of people exhibit a very strong preference for the opposite sex, and a moderate-to-significant aversion to the same sex. A tiny minority exhibit the same pattern but with the sexes switched: they have a very strong preference for the same sex and a moderate-to-significant aversion to the opposite sex.

Thus, the reason straight people aren’t having all that much gay sex isn’t because of social taboos, it’s because they’re born with an inclination to dislike it, either a little or a lot. Conversely, the reason so many closeted gay people do have straight sex is because they’ve historically faced significant social pressure to overcome their inborn inclination to dislike it.

This strong bias most of us have in favour of one sex over is not a product of social conditioning. Preferring one sex over the other is not like other physical characteristic sexual preferences — it’s not like preferring brunettes over blondes or Asians over African Americans or short people or tall people or younger people or older people. Those other things have much more to do with personal taste, which is almost completely culture-bound.

Bisexuality as a sexual orientation in its own right is a subjective term that generally describes the small number of people whose instinctual aversion to their non-preferred sex is weak enough that it’s overridden by cultural/social factors — taste, in other words. In females, aversion to their non-preferred sex is generally weaker than in males, thus females are more likely to have sexual encounters with both sexes.

Cultural factors can move the needle a little bit: if your aversion level towards your non-preferred sex is low to moderate to begin with, you’re more likely to overcome it through social pressure or in some cases lack of availability of your preferred sex. (Which is why some straight men in prison have same-sex encounters while others don’t. Same goes for teens in boarding schools, etc. Strong hormone levels and a lack of preferred-sex partners can push the moderate- to low- averse males to dabble in same-sex hanky panky.)

Young people are actually facing a lot of social pressure to identify as anything-but-straight and to even experiment with same-sex encounters to prove their liberal credentials. Social/cultural pressure to override their own aversion is playing a factor in the increased numbers of people identifying as “LGBTQ+”.

This may be music to Peter Tatchell’s ears, but I find it to be very upsetting news. No one should feel ashamed or coerced about their sexual preferences, straight or gay.