page_title: Boy
section_title: In utero development and genitalia
hierarchical_section_title: Boy / Biology / In utero development and genitalia
caption_attribution_description: English: Photo by: J. Bahnarin Salud, 2012
context_page_description: A boy is a young male human. The term is usually used for a child or an adolescent. When a male human reaches adulthood, he is described as a man.
context_section_description: In male embryos at six to seven weeks' gestation, "the expression of a gene on the Y chromosome induces changes that result in the development of the testes". At approximately nine weeks' gestation, the production of testosterone by a male embryo results in the development of the male reproductive system. 
  The male reproductive system includes both external and internal organs. The external organs include the penis, the scrotum, and the testicles (or testes). The penis is a cylindrical organ filled with spongy tissue. It is the organ used by boys to expel urine. The foreskin of some boys' penises is removed in a process known as circumcision. The scrotum is a loose sac of skin behind the penis which contains the testicles. Testicles are oval-shaped gonads. A boy generally possesses two testicles. Internal male reproductive organs include the vas deferens, the ejaculatory ducts, the urethra, the seminal vesicles, and the prostate gland.
caption: Filipino boy
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