My own son, by contrast, made his first tentative attempt at 14 1/2 months. Liam pulled himself up to a stand, turned, and took one or two steps before hurtling himself into my arms. For the next two months, cruising was an occasional curiosity; he was more content to sit on the floor and look at books. He didn't become a true toddler until he was 17 months old.
Which scenario is normal? Both of them. Walking is a motor skill with more variations than any other, and babies will master it exactly when they're supposed to -- whether it's at 9 months or 18 months. "When parents ask me what's 'normal,' I tell them that when it comes to walking, I don't even like to use the word," says David Geller, M.D., a pediatrician with Childrens Hospital, in Boston. "But I had to see hundreds of children before I understood how vast the range was."
Scientists now know that humans are genetically wired for walking. But a newborn's head is enormous in relation to the rest of his body, his center of gravity is near the chest, and his nervous system develops from the head down. So it takes about 12 months for a baby's proportions to readjust and for him to get his movements coordinated enough even to try, says Michael Wade, Ph.D., a kinesiologist at the University of Minnesota, Twin Cities campus.
While there's no definite profile of early walkers, lean babies tend to be mobile sooner than chubby ones, and those with large heads (in relation to their height and weight) usually take their first steps later. "It's physics," says Wade. But it's not just body size and muscle tone: Temperament can also determine when a baby will take his first stroll. Since laid-back kids tend to approach most developmental milestones more cautiously than their more active, restless peers, in general, infants with an easier disposition often walk later.
As long as your child has reached the skills that lay the foundation for walking, such as pulling up and standing, experts say, there's no need for concern if your child's content to crawl while most of his friends are toddling. And it's fine if your child doesn't conquer every gross motor skill in the exact order baby books suggest. "Some kids skip rolling, or scoot instead of crawl, or go from crawling straight to walking," says Dr. Geller.