A similar discussion was made back when Zachary came out and I've read way too many silly jokes about Spock being gay just because of that, it isn't even funny.
Straight actors play gay characters all the time and yet no one tells them that they can't do that because they aren't really gay. Why it should be any different for gay actors is beyond me.
If these people wouldn't able to act and pretend to be who they aren't then they wouldn't be called actors.
Have you ever watched How I met your mother?
Neil Patrick Harris is gay in real life but he still plays the character of Barney Stinson convincingly. Barney is a womanizer, it's like the foundation of his character.
Zachary Quinto had already played het characters before. Granted, Sylar was a psychopath but he had some love interests in the show and he played it pretty well.
Sexual orientation aside, it's pretty obvious that both Sylar and Spock are his very opposite but he still played them.
beside, everyone knows that he's bisex for Zoey
.. or really this
straight woman would go gay for Zoe. No kidding
. I find her that pretty.
jokes aside (not really, I'd really go gay for her
) they have chemistry and are cute together on and off screen
if they hated each other (it can happen. It happened to more iconic fictional pairs than you can imagine) it still wouldn't matter when they play the fictional characters.
I think that the biggest challenge for Zachary is to play a character that is apparently