Oops. It turns out that the currently trendy (among middle and upper-class parents) push to start teaching little babies and toddlers how to read, write, and do basic arithmetic may do more harm than good. This article in the Boston Globe details some of the latest findings. It's quite long, so I'll summarize some of the stuff I remember.
All of these efforts to start making kids smart earlier are wrongheaded because the education is not developmentally appropriate to those age groups. Research has found, for example, that children who learn how to read later on, around 6 or 7, actually become better, more enthusiastic readers in the long run. If they are "taught" too early, the children learn how to associate symbols with sounds, but that's it (that's all their brains can do at that point). Though parents may think their kids are reading, they are actually just parroting back noises, and any "advantage" in reading the kids may appear to have disappears around first grade. And kids who are part of normal kindergarten (not super-academic kindergarten), with good old-fashioned play time, become the better students over the course of their education.
Research has also shown that for every hour of things like "Baby Einstein" babies and toddlers watch, their vocabulary decreases by some percentage. Their brains are simply not ready for that, and it does not help to try and force it. What then should parents do to encourage good brain development? Keep it simple: love your kids, provide a nurturing environment, let them play, and read to them. Read to them a lot. And don't worry if your child seems like they are developing a little late...the research shows that these children often have the more advanced brain down the road.
P.S. the commonly heard "Einstein was just an average student" is misleading; though he sometimes earned average grades, he was actually a brilliant student. The problem was that he was kind of a rogue and his instructors often didn't like him. He was reading Immanuel Kant at age 14 and loving it (for context, one of Kant's books remains untranslated because the scholars who have tried have stopped for fear of losing their sanity).