Baby

As you watch your child grow and anticipate his milestones, it's natural to wonder (and even worry) about whether his development is on track ("Shouldn't he be crawling by now?" or " His sister was waving 'bye bye' by this age — why isn't he?"). But chances are that he'll develop just fine, on his own timeline.

In most instances, babies reach each developmental milestone (like rolling over, sitting, walking, and talking) right around the expected time, and if they don't they catch up soon. On the other hand, spotting potential problems sooner rather than later is important if your baby does have a genuine developmental delay.

What does "developmental delay" mean?

Doctors use this term when a child doesn't reach developmental milestones within the broad range of what's considered normal. The delay might be in one or more areas: gross and fine motor skills (such as sitting up and grasping and manipulating objects); communication and language skills (both "receptive," which relates to understanding, as well as "expressive," which relates to speaking); self-help skills (like toilet training and dressing); and social skills (such as making eye contact and playing with others).

"It's important to remember that while development tends to unfold in a typical progression — most babies crawl before they walk, make sounds before they say their first word — children develop at different rates and in different ways," says Claire Lerner, child development specialist at Zero to Three, a national nonprofit promoting the healthy development of children.

So, for example, one 7-month-old may have very advanced motor skills because he loves to explore and interact through movement but not spend much time jabbering, while another baby the same age may be playing with syllables and calling you "mama" but be less adept at motor skills. "What's most important to track is that the child is making forward progress in all domains," explains Lerner.