1. Why does the baby have thin hair? 1. Genetic factors: If parents have thinning hair, their children may also inherit this trait. 2. Malnutrition: Babies lack nutrients, especially protein, vitamins, etc., which can easily lead to thinning of hair. 3. Scalp problems: An excessively greasy or dry scalp will affect hair growth and health. 2. How to help your baby increase the number of hair? 1. Increase nutritional intake: