Thumb sucking is one of the habits that babies often have, experts say that this behavior of the baby is to simulate the process of breastfeeding. However, many mothers worry when they see their baby sucking his thumb and refusing to breastfeed, many parents are very worried, in addition, the child's thumb sucking behavior looks very unhygienic. So does thumb sucking have any effect and how to treat the habit of thumb sucking in children?