Eternal Dilemma

As you know, I work in Mergers and Acquisitions in an Investment Bank. However, I’m not the typical investment banker. At all.
The majority of my colleagues are young, single, childless and workaholic. They dedicate their life to this job, they spend nights and weekends at work (most of the time, needlessly, I must say), they have a silent competition going on to see who works more weekends, who leaves the latest. So you can often find them taking 3 hour lunch breaks, going on 4 or 5 coffee breaks a day, spending hours reading the papers or surfing the internet.

I, on the other hand, am the only married woman (and the youngest) in my department. And I have two children. I have a housekeeper/nanny who picks R up from school and stays with both kids until I come home. She works until 7 p.m., by which time I have to be home, of course. So you won’t see me taking lunch breaks longer than an hour (most likely 30 minutes) and when I’m at work I’m actually working. I truly believe that my work has not suffered in quality since I had R and I have yet to break a deadline. My boss is also happy with my work, or so he says.
However, I still get “dirty looks” when I put my coat on at 6.30 and I still have to hear all the jokes about how I have a “good life”. I’m used to it and it shouldn’t bother me but the fact is it does. I just came back to work yesterday and already I’m feeling uncomfortable about it. Why should I feel bad that I chose to have a family? Why is a person’s value judged by how late they stay at the office?