Patient: Description of the condition (onset, main symptoms, hospital visited, etc.): One year ago, she found that her breasts had grown, her nipples were protruding, and she had a hard nodule the size of a date palm. Now 19 months old, her breasts have grown again. In the past two months, she has been taking zinc gluconate oral solution, one per day. Is it precocious puberty in children? Does it have anything to do with zinc supplementation? What should we do? Do we need to treat it? Chen Yingchun: Hello! Your child is one and a half years old and used to have hard breast lumps and normal sex hormone levels. Most of them are just a special manifestation of secondary sexual characteristics, a developmental variation, and a self-limiting condition. Premature breast development is a common phenomenon in infants under the age of 2. Most children will heal on their own, and it does not cause the sexual maturation that is thought to occur. It is not directly related to zinc supplementation and currently does not require special treatment.