In 2008 there was a scandal on this topic, they unearthed the information that the girls were 13-14 years old there.
But it's still not a fact that the situation is the same now.
Maybe incorrect example, but at 16 I looked 13 years old)
Easy. In sports, this happens all the time. To be honest, I don't know if there is a scientific way to accurately determine a person's age, but even if there is, in sports such tests are not carried out. I won't say about Chinese gymnasts, but in football, fake passports are common. Sometimes they bring a 30-year-old uncle and give him off as an 18-year-old. As a rule, such a "guy" comes from Africa or Latin America. In terms of securities, he is a powerful junior, therefore, the price can be increased. For he is young, promising and dimensional. Many agents earn millions by such deceptions. But honestly, I don’t understand why it’s in gymnastics. According to the IOC rules, that 16, that 22, that 31 are all one. And there is no economic benefit.
All athletes participating in elite sports take doping. I have guys from the rocking chair near my house, who are chemists, with beards and hairy chests. And they are 16 =))) Drugs can affect the development of the whole organism. It is very common to see weightlifters with a male voice, for example.