To what extent masculinity is biologically or socially influenced is subject to debate. Although masculinity is socially constructed, some research indicates that some behaviors considered masculine are biologically influenced. Masculinity (also sometimes called manhood or manliness) is a set of attributes, behaviors, and roles associated with boys and men. Michelangelo's David is the classical image of youthful male beauty in Western art. For males during puberty, testosterone, along with gonadotropins released by the pituitary gland, stimulates spermatogenesis. Another significant hormone in sexual differentiation is the anti-Müllerian hormone, which inhibits the development of the Müllerian ducts.
Testosterone stimulates the development of the Wolffian ducts, the penis, and closure of the labioscrotal folds into the scrotum. The study of male reproduction and associated organs is called andrology. Since sperm that enters a woman's uterus and then fallopian tubes goes on to fertilize an egg which develops into a fetus or child, the male reproductive system plays no necessary role during the gestation. The male reproductive system's function is to produce semen, which carries sperm and thus genetic information that can unite with an egg within a woman. The male external genitalia consist of the penis, the male urethra, and the scrotum, while the male internal genitalia consist of the testes, the prostate, the epididymis, the seminal vesicle, the vas deferens, the ejaculatory duct, and the bulbourethral gland. The male reproductive system includes external and internal genitalia. For example, men tend to be taller than women, but there are many people of both sexes who are in the mid-height range for the species.Ī lateral cutaway of the human male lower abdomen, showing the human male reproductive system anatomy Most expressions of sexual dimorphism in humans are found in height, weight, and body structure, though there are always examples that do not follow the overall pattern. Humans exhibit sexual dimorphism in many characteristics, many of which have no direct link to reproductive ability, although most of these characteristics do have a role in sexual attraction. Sex differentiation in males proceeds in a testes dependent way while female differentiation is not gonad dependent. The SRY gene is normally found on the Y chromosome and is the testis determining factor that governs male sex differentiation. If a sperm cell carrying a Y chromosome fertilizes the female ova, the offspring will be male (XY). In humans, sperm cells normally carry either an X or a Y sex chromosome. Human males typically possess an XY combination. Karyogram of human male using Giemsa staining.