How to explain from the psychological point of view that "the dragon gives birth to the dragon, the phoenix gives birth to the phoenix, and the son of the mouse can make holes"?

Children always inherit too few genes from their parents. If the dragon didn't give birth to a dragon, you can conclude that the dragon father was on a business trip when the dragon mother was pregnant. Otherwise, why not have dragons?

If the phoenix doesn't give birth to the phoenix, it is either a phoenix or not her cub at all. Otherwise, why not have a phoenix?

It is both accidental and inevitable that the mouse's son can make holes. It is accidental that he was born in a rat's nest. Inevitably, even if he can't make a hole, his father will force him to learn to make a hole. His father can't afford to lose that man! )

Of course, heredity will happen occasionally, but most species will not change.