After the female lays one or two eggs, the male will take the first incubation shift. In species that don't build nests, the adults incubate by balancing the eggs on their feet. Incubation duties are shared between the parents in all species except one. In Emperor penguins, the male takes care of his egg for two months straight, relying on the warmth of his fellow penguin papas to survive the cold as his fat reserves dwindle. Compared to our cousins, it’s externally rather small, the head (glans) sitting within the lips (labia), and all of it hidden beneath a hood, until it is aroused. If exposed to testosterone, the genital tubercle elongates to form the penis. By fusion of the urogenital folds–elongated spindle-shaped structures that contribute to the formation of the urethral groove on the belly aspect of the genital tubercle–the urogenital sinus closes completely and forms the spongy urethra, and the labioscrotal swellings unite to form the scrotum. [22] In the absence of testosterone, the genital tubercle allows for the formation of the clitoris; the initially rapid growth of the phallus gradually slows and the clitoris is formed. The urogenital sinus persists as the vestibule of the vagina, the two urogenital folds form the labia minora, and the labioscrotal swellings enlarge to form the labia majora, completing the female genitalia. [22] A rare condition that can develop from higher than average androgen exposure is clitoromegaly. [23] Gross anatomy and histology General Created by Helen O'Connell using MRI, the first 3D image of a clitoris in an erect state with the adjacent organs of the uterus and urinary bladder Clitoris; deep dissection Kammerer-Doak, Dorothy; Rogers, Rebecca G. (June 2008). "Female Sexual Function and Dysfunction". Obstetrics and Gynecology Clinics of North America. 35 (2): vii, 169–183. doi: 10.1016/j.ogc.2008.03.006. PMID 18486835.

The clitoris of bonobos is larger and more externalized than in most mammals; [189] Natalie Angier said that a young adolescent "female bonobo is maybe half the weight of a human teenager, but her clitoris is three times bigger than the human equivalent, and visible enough to waggle unmistakably as she walks". [190] Female bonobos often engage in the practice of genital-genital (GG) rubbing, which is the non-human form of tribadism that human females engage in. Ethologist Jonathan Balcombe stated that female bonobos rub their clitorises together rapidly for ten to twenty seconds, and this behavior, "which may be repeated in rapid succession, is usually accompanied by grinding, shrieking, and clitoral engorgement"; he added that, on average, they engage in this practice "about once every two hours", and as bonobos sometimes mate face-to-face, "evolutionary biologist Marlene Zuk has suggested that the position of the clitoris in bonobos and some other primates has evolved to maximize stimulation during sexual intercourse". [189] I can’t understand why we don’t celebrate the important role the clitoris plays in our lives. I’d like to see a massive sculpture of the new 3D printed organ erected inside every science museum in the world! It seems remarkable to me that well into the 21st century we still have so much to learn about many parts of the human body.Buy, Jean; Ghossain, Michel (2013). Gynecological Imaging: A Reference Guide to Diagnosis. Springer Berlin Heidelberg. p.31. ISBN 978-3-64231-012-6 . Retrieved 11 October 2023. There is no identified correlation between the size of the clitoral glans or clitoris as a whole, and a woman's age, height, weight, use of hormonal contraception, or being post-menopausal, although women who have given birth may have significantly larger clitoral measurements. [41] Centimeter (cm) and millimeter (mm) measurements of the clitoris show variations in its size. The clitoral glans have been cited as typically varying from 2mm to 1cm and usually being estimated at four to fivemm in both the transverse and longitudinal planes. [42] O'Connell, Helen E.; Sanjeevan, Kalavampara V.; Hutson, John M. (October 2005). "Anatomy of the clitoris". The Journal of Urology. 174 (4): 1189–1195. doi: 10.1097/01.ju.0000173639.38898.cd. PMID 16145367. S2CID 26109805.

Philip Hoare, 1998. Oscar Wilde's Last Stand: Decadence, Conspiracy, and the Most Outrageous Trial of the Century Significant controversy surrounds female genital mutilation (FGM), [122] [123] with the World Health Organization (WHO) being one of many health organizations that have campaigned against the procedures on behalf of human rights, stating that "FGM has no health benefits" and that it is "a violation of the human rights of girls and women" which "reflects deep-rooted inequality between the sexes". [123] The practice has existed at one point or another in almost all human civilizations, [143] most commonly to exert control over the sexual behavior, including masturbation, of girls and women, but also to change the clitoris' appearance. [123] [144] [171] Custom and tradition are the most frequently cited reasons for FGM, with some cultures believing that not performing it has the possibility of disrupting the cohesiveness of their social and political systems, such as FGM also being a part of a girl's initiation into adulthood. Often, a girl is not considered an adult in an FGM-practicing society unless she has undergone FGM, [123] [144] and the "removal of the clitoris and labia–viewed by some as the male parts of a woman's body–is thought to enhance the girl's femininity, often synonymous with docility and obedience". [144]Smith, K. C.; Parkinson, T. J.; Long, S. E.; Barr, F. J. (2000). "Anatomical, cytogenetic and behavioural studies of freemartin ewes". Veterinary Record. 146 (20): 574–578. doi: 10.1136/vr.146.20.574. PMID 10839234. S2CID 35207213. Mascall, Sharon (11 June 2006). "Time for rethink on the clitoris". BBC News. Archived from the original on 9 September 2019 . Retrieved 22 April 2010.

Alexander, Brian (18 January 2012). "Does the G-spot really exist? Scientist can't find it". MSNBC. Archived from the original on 8 March 2021 . Retrieved 2 March 2012. Like Avicenna, Magnus also used the word virga for the clitoris, but employed it for the male and female genitals; despite his efforts to give equal ground to the clitoris, the cycle of suppression and rediscovery of the organ continued, and a 16th-century justification for clitoridectomy appears to have been confused by hermaphroditism and the imprecision created by the word nymphae substituted for the word clitoris. Nymphotomia was a medical operation to excise an unusually large clitoris, but what was considered "unusually large" was often a matter of perception. [16] The procedure was routinely performed on Egyptian women, [143] [144] due to physicians such as Jacques Daléchamps who believed that this version of the clitoris was "an unusual feature that occurred in almost all Egyptian women [and] some of ours, so that when they find themselves in the company of other women, or their clothes rub them while they walk or their husbands wish to approach them, it erects like a male penis and indeed they use it to play with other women, as their husbands would do... Thus the parts are cut". [16] 17th century–present day knowledge and vernacular A Georg Ludwig Kobelt illustration of the anatomy of the clitorisWhat about our closest cousins the chimpanzees? In common chimps and bonobos the clitoris is also a cylinder, and hidden beneath a hood, just like ours. But it’s a lot larger than a human’s. Goldstein, Irwin (1 March 2004). "Persistent Sexual Arousal Syndrome". Boston University Medical Campus Institute for Sexual Medicine. Archived from the original on 8 October 2018 . Retrieved 7 February 2013. Jocelyn, Henry David; Setchell, Brian Peter (1972). "Regnier de Graaf on the human reproductive organs. An annotated translation of 'Tractatus de Virorum Organis Generationi Inservientibus' (1668) and 'De Mulierub Organis Generationi Inservientibus Tractatus Novus' (1672)". Journal of Reproduction and Fertility. Supplement. 17: 1–222. OCLC 468341279. PMID 4567037.