Here is my theory on it. I think it has not so much do with any side effects of anal sex, but rather:
1 - some of them deliberly walk in a homo way to inticate they are gay (just like those gay hand movements they do and homo voices when they talk).
2 - with some of them its really a genetic mutation that caused them to have slightly gay features and mannarisms (Kai Greene is a good example).
3 - some of them wear very tight jeans, which can cause them to walk funny.
4 - some of them probably deliberatly walk trying to accentuate their asses, trying to attract the attention of other gays (the gay equivalent of a straight guy trying to walk with invisible lats or a puffed out chest in the hope it will attract girls...).
PS - I can already anticipate BayGMB's psychological analysis of my comments. Something along the lines of "Gib - you have obviously spend a lot of time thinking about this. You are obviously therefore gay...".
PPS - BayGBM - serious question - do you do any of those gay kind of movements or gay walking at the gym, or do you keep it more for situations less public (gay discos and meeting places etc).
PPPS - I don't mean this to be offensive to Jay Cutler (I am a fan) but does anyone else here think his voice sounds kind of gay. (I am not suggesting he is gay, just that he has a gayish voice).