Lol at 'real man' i'm sure some won't find it funny, but I know you meant no harm. If it isn't someone you plan on dating, I can't see the reason it even matters whether they are straight or gay. We are long past that. If it is, however, someone you plan on dating, I can see how it might be an issue. But it really isn't so hard these days to get a yes or no answer from gays these days, so just ask. It is a sensitive matter, more so for the person inquiring as you try not to offend someone, especially if they aren't, but I don't see any additional reasons not to ask.