You're a proud new parent and you've spent innumerable hours—months, probably, if not years—poring over parenting books. You're practically an expert on the subject now, even though your child is only a month old. You wanted to get it all just right, so you've read up on "the Mozart Effect" and Attention Deficit Disorder (ADD). You've powered through Dr. Spock. You probably have a chart up somewhere by which you're measuring your child's development against expectations. When should she grasp her own bottle? When will she say her first words? When will she walk? Run? Climb? These are benchmarks parents inevitably seek, often with much worry and doubt.

Benchmarks of brain development, though, are neither hard nor fast. The age range for some achievements can vary by months—even years. And in some cases, even if a child falls outside the range of "normal," it's not necessarily cause for alarm. Speed of development naturally varies; every child grows and adjusts to the world at his or her own pace, oblivious to the fact that the baby boy down the street, born three days later, is already regarding his own hand. Human development is no race, even if we sometimes mistake it for one.