The majority of hyena species show little sexual dimorphism, usually with males being only slightly larger than the females. The spotted hyena is an exception to this as females are larger than the males. One unusual feature of the spotted hyena is that females have an enlarged clitoris called a pseudo-penis, demi-penis or sometimes mistakenly referred to as a nanophallus. Female hyenas give birth, copulate, and urinate through their protruding genitalia, which stretches to allow the male penis to enter for copulation, and it also stretches during birth. The anatomical position of the genitalia gives females total sexual control over who is allowed to mate with them. Researchers originally thought that one cause of this characteristic of the genitals was androgens that were introduced to the fetus very early on in its development. However, it was discovered that when the androgens were held back from the fetus, the development of the female genitalia was not altered.