Why are there males and females in nature?

The distinction between male and female is a milestone in biological evolution, which makes it possible for genes to combine freely in heredity and to avoid some genetic diseases in the process of continuous reproduction. Androgyny means that half the genes of fertilized eggs come from the father and half from the mother, so that the genes of offspring are different from those of parents, and it is easier for organisms to evolve.

It should be noted here that not all living things are male and female, such as bacteria and leeches.