Are babies born without kneecaps. i'm reading in my breast feeding book on newborns and this is what they say ?

Let me explain: Newborn have knee cap. Kneecaps form about the fourth month of fetal life. However, they don’t show up on x-ray very well because they’re not ossified, or bony. At this point in life, the kneecaps are made of a cartilaginous material. The growth centers surrounding the kneecap form late in developmental life in utero and may not appear until just before or just after the infant is born.