I regularly read Female Science Professor, who often has some interesting points to make about being a woman in science. However, her readers sometimes irk me, more than a little. The comments on the post I've linked to above are a prime example.
They aren't the only comments, and I'm not even sure they're the majority of comments, but there are a decent number of people writing there who are saying some variant of "I couldn't have kids and an academic career."
Maybe you don't want both kids and a career, or maybe you've chosen a place that's bad about supporting both ambition and a family. Those are both legitimate things. If it's the first, fine, that's you're choice, and I have no problem with it. If it's the second, and you do want kids, then that sucks, and I sympathize with your difficulties--sometimes these choices get made before all the chips in the game are on the table, and I will work with you on making it a better world for women and families.
BUT: It is not impossible to have both a kid and an acadmeic career. Please do not say you can't, because that makes it seem like it's a problem with you. It's not. It's either a choice that you make (and that I don't think anyone should judge) or it's a problem with the university/department you're working with. It should always be POSSIBLE for women grad students, post docs, and professors to have kids and a career. I won't claim that it's easy, but I'm also a flawed, crazy, exhausted human being, and I can manage it.
Don't say you can't. Either you could, or your university ought to be doing the things that would make it so you could. If you don't want to balance that much, say that, and leave it at that. The next woman I hear saying "I could never do that" about my life is gonna get an earful. Yes, you could. Don't sell yourself short, because you're selling the rest of us short, too. It's not that we women can't balance career and kids--it's that there's a ton of stuff that's in our way that's not getting fixed because so many of us think that it's just us. Fuck that. It's not you, women. It's them.