Like I said, Biology is full of surprises.
Contrary to a widely held scientific theory that the mammalian Y chromosome is slowly decaying or stagnating, new evidence suggests that in fact the Y is actually evolving quite rapidly through continuous, wholesale renovation. The analysis was possible because of the sequencing of the Y-chromosome from Chimpanzees.
The region of the Y that is evolving the fastest is the part that plays a role in sperm production, the rest of the Y is evolving more like the rest of the genome, only a little bit faster.
The paper is in Nature this week and there is a nice write-up at ScienceDaily.