Brave, Stupid, or...

I know a family that had 2 healthy, happy, bratty kids. Then they decided to have a third. After several miscarriages, stillborns and a doctor telling them that it is not advisable for them to conceive again, they had another kid. "Special" and wheelchair bound for life, the kid had a wheels strapped to him to just to crawl. Just now I saw that went ahead and had a 4th child, which I don't quite understand. You love your kids no matter what (while I don't have a kid to know this, my parents love me, and I'm me, which is definitive proof in my book,) but I don't know what goes through people's minds. They're either brave, stupid, or just plain don't believe in birth control.