My experiences are completely dissimilar. My wife is one of my players, and obviously that means there's no "hitting on her" factor (esp. as all but one of the players are married or in long-term relationships), and I've seen absolutely no holding of extremely obscene jokes, unfair allegations regarding character parentage/sexuality/special interests, or what-have-you.
She's a good player, and whilst a little retiring in D&D because she's not entirely sure what she's doing (very experienced MMORPG and CRPG player, not so much P&P RPG), certainly contributes to the game significantly. I don't think there'd be any problem if any other female SOs joined in, either, given we all socialize together and are reasonably comfortable with each other. The only potential problems I could see would be if people who didn't want to play were being brought in.
Basically, it's a matter of familiarity and whether the players themselves are stable. Suddenly add a "hot gurl" to a mostly-teenage, mostly-nerdy group is gonna have an impact, and it won't necessarily be for the better initially. However, unless the players have serious problems, by the second or third session, the impact will be over.
Tbh, whilst ymmv, the main thing to do is to not be playing with scary non-social-skills nerds who are either gynophobes or freaks. So long as that's the case, any disruption will be over soon.