I'd like to know more about the crime vs unwanted pregancy theory (link above). It makes sense to me because the point is really whether or not a woman wants a child. Could it be true that abortion has reduced the crime rate? If so, it seems that the only thing we have to worry about is whether or not a woman wants a baby because unwanted children have more of a chance of becoming criminals.

As Don said, caring and educating children is security for your old age. If they do not receive adequate food, shelter and clothing, they will not be able to contribute to society in a meaningful way.