Question 1: The baby is just 5 years old this year. He always loves to play with his penis and make it erect. I didn\’t pay attention to it at first, thinking he was just curious, but later I found out that he always likes to lie on his stomach when lying on the bed at night, always shaking his penis there, and he would break out in a sweat after a while. His teacher also said that he liked that in school too. I would like to ask if this is premature maturity? What should I do? Dr. Luo Zhen answered: This is equivalent to masturbation, but the child does not know what masturbation is. He only knows that there is a certain amount of pleasure in doing so. The main reason is psychological loneliness and lack of companionship. Therefore, parents should communicate with their children more often, play with them, tell stories, play games, etc., to divert their attention. Never mention it to your child, he will slowly forget this problem. You can let your baby wear underwear when sleeping, and also put on underwear for your baby at ordinary times. Question 2: The baby is one and a half years old now. One of his little balls is on top and the other is on the bottom. What’s going on? Will you come down by yourself? It hasn\’t come down in the past few days, but now it comes down again. Is it normal? Dr. Luo Zhen answered: Now we need to do a color ultrasound of the baby\’s testicles to see if there are any problems. If there are no problems, you can usually wait and see. If the testicles have not fallen after two years old, surgical treatment is recommended. Generally, the problem is not serious. If the problem persists in the future, surgical intervention can be performed without any impact. Question 3: I have two children in my family. The eldest boy is four and a half years old, and the second boy is about ten months old. If one child is sick, such as sneezing, runny nose, cold, fever, cough, vomiting, etc., does the other child need to be isolated? What if necessary is to effectively isolate? Or do some diseases require isolation (such as colds and coughs), while others do not (such as gastrointestinal diseases, diarrhea, vomiting, etc.)? Dr. Xu Lijuan’s answer: Sneezing, runny nose, and coughing are respiratory infections that are spread through respiratory droplets, so isolation is required. Isolation mainly involves avoiding close contact, such as kissing, face-to-face sneezing, coughing, etc. Intestinal infections and dysentery are infectious diseases that are mainly transmitted through feces and mouth. If water hygiene and food hygiene are done well, the infection will generally not occur.