I never knew you all had such a pent-up demand to discuss matters gay. Having read through 110 plus comments, I am now more inclined to see genetic correlations — rooted in the human mind rather than the body — with athletic achievement (NB: I don’t agree with all the "genetic" claims in the thread, by any means).
Most of all, I am struck by how few former male athletes have come out of the closet. That would seem to adjust for "the locker room effect" and "the endorsement effect," as explained in my original post. Once an athlete is retired, those factors shouldn’t matter much.
I also noticed that Amaechi signed a book contract about being gay in the NBA. He was a pretty feeble player, and quite nerdy, more here. How large was his book advance? 50K or 100K is not a bad guess. I’ve known plenty of gay guys who would self-identify for much less; the fact that so few former male athletes have done so is striking.