One and a half year old baby has white hair may be genetic factors, but not absolute, may also be mental factors, malnutrition, disease factors. 1. Genetic factors: parents in the age of a relatively small child on the appearance of white hair, and grow more, may be autosomal dominant inheritance, one and a half year old baby with white hair may be genetic factors caused by the beginning of a few scattered white hair, and then gradually increased. 2. mental factors: one and a half year old baby long white hair in addition to genetic factors may also be other reasons, frequent changes in the family to raise or change the living environment, stimulate the baby’s mental state is not stable, often anxious, often crying, may also be long white hair. 3. malnutrition: one and a half year old baby excessive picky eaters, there is malnutrition, the body lacks copper, iron, protein, vegetable oils, vitamins and other nutrients, so that the number of melanocytes in the hair follicle is reduced, the function of the hair follicle is affected by the appearance of gray hair. 4. Disease factors: one and a half year old babies suffer from their own diseases, such as pituitary dysfunction, thyroid disease and other endocrine disorders, will also grow white hair. One and a half year old babies have gray hair for more reasons, whether hereditary to go to the hospital through the examination to determine.