What on earth are you on about? Gay actors play straight roles all the time and it's not much more of a challenge (probably much less so actually) than for a straight actor to convincingly play a gay role which also happens regularly. No idea what rock you've been living under, but, for your information, acting is not limited by an actor's se.xuality. And if someone cannot pull it off, it's due to their lack of talent and not because of their orientation.

Wait! Is that Lance Bass? Cause if it is and if this movie is ramtic comedy masterpiece some people think it is, then that man is an Oscar worthy actor convincing anyone that he has even one moment of feeling below the belt for this girl would be a Herculean feat in and of itself. Couldn't get away with that today though. You imagine the uproar if an openly gay man got the role of a straight white dude when there are so many capable cisgenderered male actors begging for roles? It's not 1992 anymore, when will the straight white man catch a break?