Baby Physical Development and Bowlegs
This question comes up for most families during the first year of life. It's actually a very common grandparent question because a lot has changed in the years since they raised children, when many infants were put in braces—often unnecessarily.
Almost all infants have bowed lower legs (legs that curve inward) due to the cramped quarters they lived in for the last weeks of gestation. Since the majority of babies are born headfirst, they spend the last weeks in your uterus with their legs crossed and folded against their abdomen—when they aren't kicking you in the ribs, that is! This results in a bowing of the still very soft fetal leg bones.
This bowing of the legs will straighten out with the pressure of gravity once the child begins to walk, but it often takes many months of walking to achieve this. Much less commonly, a baby will have bowed legs due to a medical problem, such as rickets (the result of a vitamin D deficiency), an underlying bone disorder or a rotational problem (such as the way the leg bones insert in the hip sockets). These are more likely to be the problem if one of your baby's legs is very different from the other or if your child is showing some other kind of growth problem. As always, you should discuss your concerns with your pediatrician, who can usually eliminate any worries with a good physical exam.