Yes, they are more fecund than the average American family. Whatever family size works for you, but just pointing out that at this rate, they're going to outnumber us.
Erm, the link doesn't work for me. This is a problem, actually, because there is research that shows a genetic component to political partisanship. But the bigger problem is that liberal, well-educated women aren't having as many kids as they might want because of the issue of childcare. They're certainly not going to give up their livelihood in order to have more kids—subsidized childcare would begin to tackle this issue. Seriously, it's like the closest thing we have to a magic pill.