I don't really have a question but I was chagnign my nephew's diaper yesterday (he's 1 this month) and noticed that he was casually, um, touching his stuff, like it was just something to do to pass the time as I put on his new diaper.  So when you said, "Why are babies fascinated by balls?" that is how I read that question.  Is does offer some insight to the mens. Apparently this is behavior they learned from very early on.
