As My Mother Always Complains, "It's Always The Mother's Fault!"

Conditions in the mother's womb seem to influence a son's sexual orientation. In particular, the more older brothers one has, the more likely one is to be homosexual. But what about lesbian daughters and homosexual sons without older brothers (such as myself)? There must be other factors (which I don't think any scientist, including the ones who did this study would disagree with).