I think its LESS of a problem if you're a woman and you already have kids. There's no fear that you'll miss a bunch of time for maternity leave (you've already birthed your children), and much less likely to leave the firm completely to be a stay at home mom, again, since you have kids already and are still choosing law school/career, whatever.
As a woman, though, I have to add that I would much rather these kinds of considerations never come into play in a hiring/retention decision.