Breeding for politics?

I thought this was a pretty interesting article in today's paper:

Republicans' fertile future.
Through the past three decades, conservatives have been procreating more than liberals

The summary: republicans have more babies than democrats do. The question: does that mean as time goes on, the dominating political party will be determined by breeding?

The article says 4 out of 5 children take on the political viewpoints of their parents. I think that nowadays, that number may be a little high, due to the rapid spread of information. So maybe things like the internet will help people make up their own minds more often.

It's pretty common knowledge that people have had (and still have) babies in different societies for motives such as prestige, money, social standings, etc. But I guess I just never thought of this particular point of view. Could this have anything to do with the conservative anti-birth control, pro-young marriage, etc., view points? Or is it really more environmental (it's not nearly as easy to raise a family in densely packed urban areas which are typically more democrat)?

I wonder if any studies have been done on this throughout U.S. history? Are the U.S. political changes throughout history largely due to certain populations having more children? That would be quite an interesting discovery...