Kiprobalhato wrote:
i think it's biologically based, we evolved to disapprove of homosexuality because it doesn't make babies.
If you expect group selection to operate, maybe. But most evolutionary biologists agree that group selection works only under restricted and rare conditions.
If selection of attitudes towards homosexuality operates at the individual or the gene level, then people should approve of homosexuality among people of their own sex, because it reduces competition, with the exception of their close relatives, where it may reduce inclusive fitness. "May" because if your sibling were homosexual and had no children, but their help in raising your children increases your reproductive success by 50%, then your inclusive fitness is the same as if your sibling had the average number of children (assuming your reproductive success would otherwise have been average). In that case, you shouldn't mind a sibling being gay. General homophobia looks like a bit of an evolutionary puzzle to me.
Also, a substantial proportion of men prefer women who have some sexual interest in other women. There is speculation that the evolutionary basis could be that the man might get lucky with his partner's female partner. I don't know whether any data support that speculation.
You would expect that parents disapprove of exclusive homosexuality among their own children, again because of reduced inclusive fitness. Unless exclusively gay offspring's help to their siblings can be expected to increase the number of grandchildren among the not exclusively gay children by the average number of children, or more.
Given the male preference, parents should have evolved to approve of their daughters being bisexual.
If a bisexual son's male partner can be axpected to contribute to raising grandchildren, they should also approve of sons being bisexual.
Theoretically, how many babies get made by whom should be relevant to any evolved component of homophobia, but I think it's a bit more complicated than you outlined. And then, any evolutionary account of homophobia would have to show that it is a universal trend across cultures. Which doesn't seem to be true:
https://twitter.com/Diamandahagan/status/1054501242045652992.