Hey now, with the dog population the way that it is why would you deny those puppies a good and loving home?
To OP: Your dog is not gay, he is of the lower animal kingdom and relies mostly on instinct. His mounting of another male is a symbol of dominance not gayness. I suggest you "whack his pee pee" (just a euphemism....PETA members...chill) when he does this otherwise you will no longer be the 'alpha' in your relationship with your canine.
I assume your dog also has the hots for stuffed animals, women's legs, etc.? I'm not quite convinced dogs have sexual preferences.
According to my vet it's not deviant behavior but a way of showing dominance, top of the pack so to speak, to the other dog.