Babies are born with kneecaps, but these kneecaps are not hard bones; they are made of soft cartilage. This cartilage gradually turns into bone through a process called ossification. Most children's kneecaps begin to ossify and develop into solid bone between the ages of 2 and 6 years, with the process continuing slowly over several years. By around age 10 to 12, the kneecaps are typically fully developed into bone, though a small part may remain cartilage or fatty tissue. This soft cartilage at birth allows babies to move more easily and safely as they learn to crawl and walk without risking injury from rigid bones.
