When one of them says loudly enough for me and others to hear, "Your daughter sounds like a real bitch! hur hur", I turned to them and said, "You guys need to knock this off now."
Embarrassed silence. And it stayed that way. Of course, I'm a tall well-built, well-dressed white guy, i.e. all the things that automatically command respect.
The thing is, I don't think those guys were bad people, I don't think they sat there in their minds thinking, "let's tear the woman down". I really don't think they thought about it at all. I also don't think they'd have sat there, chattering away, if a man had used the same framing story (father and son, father and daughter).
I think there's a lot of unconscious, unconsidered, unthoughtful bias that they (and we) all carry around by default, that makes it easy to pick on weaker people if you're going to pick on anyone. And there are a lot fewer women around these tech conferences, and they're used to placating aggressive people, putting up with shit, etc.
I guess, I wish women didn't have to talk about being a woman in tech. I hope they keep doing it, though, until people start thinking about this kind of asinine behavior.