Alright. Here we go. This will be exciting.
-copy/pastes from Facebook-
Okay. I will do my very best to shoot down the gay!Sheldon theory with what I know of the show now (I'm halfway through series 2). 'Kay?
Sheldon is the kind of person who (until he gets what his dearly-beloved actor called... what was it? A frying-pan-to-the-head moment?) considers... romantic entanglements as useful only in the context of reproduction. As offspring cannot be gained through a homosexual relationship, he would regard the practice as superfluous. After all, if he doesn't figure out a way around dying (wouldn't put it past him), his intellect will only be able to survive via his genetic... whatnot.
Which means that either he's going to clone himself (also wouldn't put it past him), or engage in some kind of reproductive activity that would result in offspring.
And as, barring Whatshername, the only female he has any kind of substantial regard for is Penny... SHENELOPE FTW, FEMININE CANINES.