I'm not sure I've ever been overly ambitious - at least not realistically, since I know there's a limit to how driven I am and that I'm not one of those people who will do "whatever it takes." But I can't say at this point whether that's an outcome of having kids...I just know that family and balance are more important to me than getting to the top of the heap at work. And since last October, I've been married to someone who feels the same way, which is very nice.
There's a fuller discussion in my essay here. You have to be a member of the site to rate/vote on an article.