The "tiger mom", the Yale law prof who talks about pushing her two daughters to perfection by behaving as a "Chinese mother" is getting lots of attention. I'm also reading Condolezza Rice's memoir, which describes how her parents pushed her and pushed her (it's interesting, not great, but interesting). This ties into a Tyler Cowen post on a study which indicates that environment makes the most difference for people in less fortunate conditions while genes make more difference in the more fortunate conditions. (Think of this example: if food is scarce, you don't get many tall basketball players; if food becomes plentiful, genes for height can be fully expressed. Stole that from a book I read which I'm too lazy to look up.)
Over my lifetime parents have invested more and more effort into rearing their children and giving them advantages. I think that's a reflection of the good times we enjoy. In the 19th century, a good parent was a good provider or a good homemaker. Do those things well and the environment would take care of your kids. Now with most Americans middle class or better, the competition is stiffer. But because less is under the parents' control, there's more premium on the margins. It's rather like athletes in track. When I was growing up, the times for the mile were being lowered slowly. Then came Bannister and Landy and the breaking of the 4-minute barrier and then fell quickly. Now it takes more and more effort and training to eke out any world record in either the mile or 1500.