While teaching 4-year-olds the alphabet or numbers would seem to give them an advantage when they enter school it often can turn kids off to education.

"Pushing early academics appears to be worthless at best," says Lawrence Kutner, a clinical psychologist and author of "Parent & Child: Getting Through to Each Other (Morrow). "At worst, it can change a child's image of school from an exciting place to a place filled with failure and stress."The problem is that memorizing letters does not teach a child to read, says Kutner. "What leads to reading is having stories read to you, making up stories and seeing labels on objects so you can connect the printed word with the object."

The same can be said for mathematics, he says. "Rote memorization of numbers or two-plus-two is often less valuable than spending time playing with blocks."