Why doesn't my baby have hair?

A better...: A better question is, what does he need it for? There is wide genetic variability in how much hair a newborn has or when it begins to grow, and the elders of your family will probably remember how bald either or both parents had been back then, but all babies will have a full head of hair by 2 years at the latest.

Normal cycle: A lot of babies are born with hair, some without, but a normal part of the growth phase of the hair makes it fall out at about the 4-6 mo mark. Not for all but some. Around 9 mo or so, it starts to grow back in, and fills out according to family genetics. Sometimes a bad case of cradle cap can cause hair loss too. On the back of the head, rubbing can cause temporary hair loss. It comes back.

A familial trait: The color, amount, and location of hair is usually genetically determined, and thus is a familial trait. If a baby truly has no hairs, is covered with too much hair, or has a very odd hair texture or strange pattern of hair growth, then medical evaluation is needed to see if other hormonal or genetic problems are present.