Infants’ upper teeth may be affected by genetic factors. Generally, as long as the teeth erupt at the normal time and the quality of eruption is good, there is no need to worry too much. Infant teeth erupt at the age of half a year to about two and a half years, for most infants eruption is generally the lower teeth and then the upper teeth, but the order of eruption is not exactly the same, for individuals, affected by genetic factors and individual development, there may be the case of eruption of the upper teeth before the lower teeth, but as long as the normal eruption, there is no developmental defects of the teeth, there is no need to be too worried. Infants grow teeth first upper teeth often due to individual differences in the situation and the differences, if the teeth erupt normally, generally do observation.