I've had several people ask me what I think about the gay younger brother study. Usually, they preface it with something like, "Isn't this ridiculous? You don't have any older brothers do you?"
But I don't think it's ridiculous. The study was prompted by a statistical fact: men who have several older brothers are much more likely than other men to be gay. It doesn't mean all gay men are younger brothers, but it does mean younger brothers are likely to be gay.
Scientists being scientists, this fact intrigued some of them and they wanted to see if they could figure out why. So, they interviewed a bunch of gay younger brothers and their families, to see if there might be some environmental factor at work. Turns out, they couldn't find any common environmental denominator. They also ruled out genetics, so now they think it must have something to do with the environment of the mother's womb.
It's not the sort of thing I'd spend time studying, but it seems like a pretty reasonable conclusion to me. It also cuts against the ex-gay "bad parents" theory. And, as a survivor of ex-gay therapy, I think anything that debunks that pseudo-science is a good thing.