Well you found me out!
In 2011 (last #'s I've seen) there were 594,355 children collecting a combined total of about $7,132,260,000 per year and 2,291,792 collecting $27,501,504,000 on their spouses record.
It must be an "overseas thing" for the most part, as all of my married friends (age 60 and older) all have young wives and only five or so with young children. The oldest is 74 with a 36 y/o wife and a two year old daughter, He is a German national and we have never discussed his benefits. In the States my two closest friends have young Wives 62/26 and 62/40 but neither of them are retired or have children with their 2nd and 3rd Wives.
If we move to Texas as we are planning, I'll be sure to drop by with the missus and say hello!