Bow Legs / Knock KneesAlthough infants are born with bowlegs, where the knees appear to “bow” out from the body, the knees tend to straighten out between 18 and 24 months of age. In turn, when most children begin to walk — at around 12 months of age — they appear to be bow-legged.
Knock-knees, on the other hand, are when the knees appear to bend toward each other. If a child is knock-kneed, it will be most evident when he or she is around 3 years of age, and will then gradually become less pronounced. By age 7, they will have attained the normal adult amount of slight knock-knee — 5 to 9 degrees — which they will maintain throughout their life.