Strong Bodybuilding Man Portrait

The term primary sexual characteristics denotes the kind of gamete the gonad produces: the ovary produces egg cells in the female, and the testis produces sperm cells in the male. The term secondary sexual characteristics denotes all other sexual distinctions that play indirect roles in uniting sperm and eggs. Secondary sexual characteristics include everything from the specialized male and female features of the genital tract, to the brilliant plumage of male birds or facial hair of humans, to behavioral features such as courtship.
Biological factors are not sufficient determinants of whether a person considers themselves a man or is considered a man. Intersex individuals, who have physical and/or genetic features considered to be mixed or atypical for one sex or the other, may use other criteria in making a clear determination. There are also transgender or transsexual men, who were born or physically assigned as female at birth, but identify as men; there are varying social, legal and individual definitions with regard to these issues.
• Reproductive system
The male sex organs are part of the reproductive system, consisting of the penis, testicles, vas deferens, and the prostate gland. 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. 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 concept of fatherhood and family exists in human societies. The study of male reproduction and associated organs is called andrology.