People's looks are mainly determined by genes. Parents are beautiful, but children are generally not ugly. Plastic surgery only changes the surface tissue structure, shifting local tissue has a magical effect, and people who are not good-looking are also beautiful. But it didn't affect the genes.

On the other hand, people's looks are relative, just a comparison between one person and another. A mother without plastic surgery has many similarities with her children, so there is not much difference between them. If the mother had plastic surgery, she would be much more beautiful than herself, and certainly more beautiful than her own children. This contrast difference is equivalent to the difference before and after the mother's plastic surgery.

Therefore, some people will come to such a conclusion.