[JabavuAdams]

Why do we assume that non-majority sexualities are genetic? As society relaxes wrt sexuality, we may see that many more people who do not identify as gay per se may openly display flexible sexuality.

E.g. saying you're left-handed is no big deal anymore. One day one's sexuality may be equally irrelevant.

[int_19h]

We don't assume it; we are still studying this extensively, and so far more evidence seems to be in favor of nature vs nurture.

If it were a matter of "relaxing", you'd expect that children raised in homosexual families would tend to be more open about flexible sexuality, and more would identify as gay, or at least as non-hetero - but that is not the case. The ratio of children becoming homosexual vs heterosexual is the same in both homosexual and heterosexual families, insofar as our studies can identify. At the same time, there have been some observed correlations between sexuality and specific genetic markers.

Really, the more interesting question at this point is whether it's mainly genetic, or mainly epigenetic.