An outward curving of bones in the legs that results in wide separation of the knees when the feet are together. Bowlegs are common in very young children and are a normal part of development. In most cases, the curve straightens as the child grows. If the bowing is severe, is on one side only, or persists beyond the age of 6, a doctor should be consulted. Surgery may be needed. Rarely, leg deformity is a result of bone disease, particularly rickets (a vitamin D deficiency) in children.