Three and a half years old boy that height 98cm, not low, belong to the normal range. According to “0 ~ 18 years old children and adolescents height, weight standard deviation unit value table (male)” in the three and a half year old boy’s height between 96.7 ~ 104.5cm are in the normal category, so three and a half year old boy’s height of 98cm is not too low, is normal. Boys’ height is closely related to genetics, nutrition, disease and living environment. Parents can continue to pay attention to the growth indicators and draw growth curves in order to detect growth and development problems and intervene in a timely manner. If you have any questions about your child’s growth, a professional clinician should conduct a comprehensive assessment, do not trust others or self-medication to avoid adverse effects on the body.