In reply to:
Ever heard of shades of gray?
The grey area is indeed pretty large. If you look at the Kinsey study (I think the main a2a page talks about it...), it's very definate that there's no absolute answer to it.
Basically, emotion attraction is much less important than physical attraction in determining sexual orientation. Even more simplified, it's whoever 'gets you up.' Emotional attraction without physical attraction doesn't really work in the long run. Physical attraction without emotional attraction can work however, so that means that sexual orientation is more based in physical attraction rather than emotional attraction.
So to apply this to the original post...One act doesn't make you gay... numerous acts don't make you gay, it's whether or not you're attracted to men in general that would make you gay.