I don't really care. Its a normal bodily function. If farting is enough to drive a guy away, then I don't want to be with that person anyway.
I had guys who made a huge deal about it, when they wouldn't think twice about letting it rip near me. Also my boyfriend has even farted on me, so I have no idea how someone could get offended by it.
It's one thing if they hate all farting, but to say that only girls can't fart, that's pretty ridiculous, IMO. Unladylike? Perhaps, but it's not unhumanlike. So I don't know why it's such a big thing with some guys.