Why does Tik Tok always recommend videos of giving birth to sons?

Tik Tok has always recommended the video "Having a Son" for the following reasons:

Because you've been watching the same kind of content. In addition, the videos you brushed are all of the same type, or you searched alone, and then you watched many videos of the same type. Tik Tok has personalized recommendation, and will recommend videos to you according to your attention or your search, and the maximum number of times you play similar videos.