[5] Except for humans, a similar structure known as a penile sheath appears in the male sexual organs of all primates and the vast majority of mammals.

The inner foreskin is a continuation of the epithelium that covers the glans and is made up of glabrous squamous mucous membrane, like the inside of the eyelid or the mouth.

[16] The human foreskin is a laminar structure made up of outer skin, mucosal epithelium, lamina propia, dartos fascia and dermis.

[28][29] The penis develops from a primordial phallic structure that forms in the embryo during the early weeks of pregnancy, known as the genital tubercle.

[30] Initially undifferentiated, the tubercle develops into a penis depending on the exposure to male hormones secreted by the testicles.

[37] The earliest report by Schweigger-Seidel (1866)[38] and later Hunter (1935)[39] suggested the formation of the prepuce out of dorsal skin and its progressive distal extension to completely cover and eventually fuse with the epithelium of the glans.

[37] Glenister (1956)[40] expanded the theory suggesting that the preputial fold results as an ingrowth of the cellular lamina, which rolls outwards over the glans, but with the resultant preputial lamina also expanding backwards to form an ingrowing fold at the coronal sulcus.

[44] By sixteen weeks, the bilateral preputial folds cover most of the glans and the ventral sides of the prepuce fuse in the midline.

[35] Towards the end of the second trimester,[48] the glans and the prepuce have completely fused together by the preputial, sometimes referred to as balanopreputial lamina.

[49] At birth, this shared membrane is physiologically adherent to the glans preventing retraction in infancy and early childhood.

[50][51] The phenomenon of non-retractile foreskin in children naturally starts to resolve in varying ages; in childhood, preadolescence or puberty.

[57][58] The phenomenon of non retractile or tight foreskin in childhood, sometimes referred to as physiologic phimosis,[51] may completely resolve before, during or even after puberty.

[9][59][55] When the foreskin starts to become retractile, a pediatrician can recommend careful retraction at home and rinsing with water during bath.

[52] During puberty, as the male begins to sexually mature, foreskin retractability gradually increases allowing more comfortable exposure of the glans when needed.

Gentle washing under the foreskin during shower and maintaining good genital hygiene is sufficient to prevent smegma buildup.

[61][57] Smegma is an oily secretion in the genitals of both sexes that maintains the moist texture of the mucosal surfaces and prevents friction.

[69] The World Health Organization (WHO) stated in 2007 that there was "debate about the role of the foreskin, with possible functions including keeping the glans moist, protecting the developing penis in utero, or enhancing sexual pleasure due to the presence of nerve receptors".

[73] In 1949, British physician Douglas Gairdner noted that the foreskin plays an important protective role in newborns.

[73] The College of Physicians and Surgeons of British Columbia has written that the foreskin is "composed of an outer skin and an inner mucosa that is rich in specialized sensory nerve endings and erogenous tissue".

A condition called paraphimosis may occur if a tight foreskin becomes trapped behind the glans and swells as a restrictive ring.

[79] Lichen sclerosus is a chronic, inflammatory skin condition that most commonly occurs in adult women, although it may also be seen in men and children.

Topical clobetasol propionate and mometasone furoate were proven effective in treating genital lichen sclerosus.

[91]: 181 Foreskins obtained from circumcision procedures are frequently used by biochemical and micro-anatomical researchers to study the structure and proteins of human skin.