Masturbation in female mammals, as well as heterosexual and homosexual intercourse (especially in primates), often involves direct or indirect stimulation of the clitoris (as in the description at the beginning of this section of oral sex among Siamangs, a primate species). This organ is present in the females of all mammalian species and several other animal groups, yet it has generally elicited a uniform reaction throughout much of scIentific history: stunned (and embarrassed) silence.150 This is due not only to the general hush surrounding female sexuality, but because the clitoris poses serious challenges to conventional biological theories. Its only "function" appears to be sexual pleasure, and the notion of pleasure in animals, particularly as it relates to the phenomenon of female orgasm, is a difficult one for biologists to come to terms with. Scientists have been remarkably reticent on the subject, refusing even to believe that female animals can experience orgasm until the phenomenon was "proven" with detailed observations and experimental studies on monkeys.
Even after it was "verified," a debate about the "function" of the female orgasm erupted in the scientific community and continues nearly unabated to this day. When a male animal has an orgasm-i.e., ejaculates-this is typically explained as the "mechanism" that insures sperm is transferred to the female-not as the pursuit of sexual pleasure. But no such mechanistic "explanation" is available for the female orgasm or clitoris. Most current biological discussion of the female orgasmic response attempts to justify its existence in terms of how sexual pleasure might "encourage" or contribute to breeding or social bonding, rather than seeing it as something inherently valuable that requires no further "justification." As always, female sexuality-and sexual pleasure in general-is assumed not to exist until proven otherwise. Once "proven" it requires a "function" or "purpose" rather than having intrinsic worth-a striking echo of the presumption of heterosexuality in biology and the need to find an "explanation" for the occurrence of homosexuality.