Human penis size
Human penis size is talked about by length and circumference of penis. It is longer than in other primates except for the chimpanzee. The chimpanzee's penis is about the same length. The penis is bigger in circumference on humans than on other primates. One reason suggested is that human women prefer males with larger penises, so men with larger penises get more chances to have sexual intercourse, and more children, than males with smaller penises. Since humans commonly face each other when having sex, it is not really necessary for human males to have long erect penises. Short penises work just as well.