Theoretically, the gender differences between men and women, especially the primary sexual characteristics, can be answered before children reach puberty. Judging from the current social and cultural situation, it is best to answer the gender difference before the age of 5. No matter how advanced sex education is, it is also inseparable from children's understanding ability.

2. Appropriate methods

Children can speak with their parents' bodies before the age of 5, but after the age of 5, it is best to use books, audio-visual materials and other methods.

3. Appropriate content

Children's sex education should focus on the contents of all ages. Simple problems such as gender knowledge should be solved before the age of 5. Sexual physiology education should be carried out before puberty, and sexual psychology and moral education should be carried out during adolescence.

In a word, sex education for children should adhere to the natural and appropriate principles, and we should not deliberately look at children's problems from the perspective of adults.