Anonymous

Females chose the general size of the human male penis through selection. Females would mate most often with males of a certain genital size, thus continuing the genes of that size penis. Why? Women knew what they were doing.

Anonymous

For two million years, humans were lesbians and then men evolved dongs.

Anonymous

Simple. If the male and female do not "mesh" there is no reproduction and the genes for the unmatched genetalia are not passed onto the next generation.