The clitoris (/ˈklɪtərɪs/ ⓘ or /klɪˈtɔːrɪs/ ⓘ) is a female sex organ present in mammals, ostriches and a limited number of other animals. In humans, the visible button-like portion is near the front junction of the labia minora (inner lips), above the opening of the urethra. Unlike the penis, the male homologue (equivalent) to the clitoris, it usually does not contain the distal portion (or opening) of the urethra and is therefore not used for urination. While few animals urinate through the clitoris, the spotted hyena, which has an especially well-developed clitoris, urinates, mates and gives birth via the organ. Some other carnivorous animals, or mammals in particular, such as lemurs and spider monkeys, also have a well-developed clitoris.
The clitoris is the human female's most sensitive erogenous zone and generally the primary anatomical source of human female sexual pleasure. In humans and other mammals, it develops from an outgrowth in the embryo called the genital tubercle. Initially undifferentiated, the tubercle develops into either a penis or a clitoris, depending on the presence or absence of the protein tdf, which is codified by a single gene on the Y chromosome. The clitoris is a complex structure, and its size and sensitivity can vary. The glans (head) of the human clitoris is roughly the size and shape of a pea, and is estimated to have more than 8,000 sensory nerve endings. (Full article...)