<P> The testicle or testis is the male reproductive gland in all animals, including humans . It is homologous to the female ovary . The functions of the testes are to produce both sperm and androgens, primarily testosterone . Testosterone release is controlled by the anterior pituitary luteinizing hormone; whereas sperm production is controlled both by the anterior pituitary follicle - stimulating hormone and gonadal testosterone . </P> <P> Males have two testicles of similar size contained within the scrotum, which is an extension of the abdominal wall . Scrotal asymmetry is not unusual: one testicle extends further down into the scrotum than the other due to differences in the anatomy of the vascululature . </P> <P> A length of a testicle can be measured with an orchidometer . Its volume is 15 to 25 ml. Template: Needs reference There is some evidence to suggest that average human testicle size and weight has been progressively diminishing in recent years among younger cohorts in Western industrialized nations . This may be associated with a decline in sperm counts . The recent changes suggest involvement of environmental or lifestyle factor (s) such as increasing exposure to endocrine disruptors . </P> <P> In healthy European adult humans, average testicular volume is 18 cm3 per testis, with normal size ranging from 12 cm3 to 30 cm3 . The average testicle size after puberty measures up to around 2 inches long, 0.8 inches in breadth, and 1.2 inches in height (5 x 2 x 3 cm). Measurement in the living adult is done in two basic ways: </P>

What is the normal size of human testis
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