Math Problem

I read about China's Population Problem, and began to wonder about the gender imbalance. Putting aside the ugly moral problems involved (and the horrible practice of infanticide of baby girls), the question can be a fairly straightforward probability problem.

In urban areas, families are limited to one child per couple. But in rural areas, there is a one boy/two children limit. If your first child is a boy, you are done. But if your first child is a girl, you may have a second child.

Would this policy lead to any gender imbalance in and of itself?