There is a Italian study that shows mothers of gay men are quite a bit more likely to bear many children than mothers of only hetero children. Their conclusion

There is a Italian study that shows mothers of gay men are quite a bit more likely to bear many children than mothers of only hetero children. Their conclusion is there at least a partial genetic component, likely coding for "Likes to have sex with men" that the gay men just happen to get as a side effect of the very effective gene for women.