Baby’s lack of teething may be caused by genetic factors, calcium deficiency, developmental time and other reasons. 1. Genetic factors: If there is a genetic background for late teething, the baby may teethe later. If the parents have late teething, the baby also has a tendency to grow teeth late. 2. Calcium deficiency: It may be due to the loss of calcium in the baby’s body, which causes symptoms such as slow growth of teeth, leg cramps and leg pain. 3. Developmental time: It may be due to the fact that babies are not yet at the age when they should grow teeth, so they do not grow teeth. This is a normal physiological phenomenon and usually does not need to be dealt with. Babies do not grow teeth may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.