The Human Reproductive System

The reproductive system enables humans to produce offspring and differs between the sexes. Its organs are coordinated by hormones and become fully active during puberty. Unlike other organ systems, it is not essential to keep an individual alive, but it is essential for the continuation of the species. Sex cells, or gametes, carry half the usual number of chromosomes so that a full set is restored when egg and sperm combine.

The male reproductive system produces and delivers sperm cells. The testes, held in the scrotum, make sperm and the hormone testosterone. Sperm mature in the epididymis and travel through the vas deferens, mixing with fluids from the prostate gland and other glands to form semen, which leaves the body through the urethra in the penis. The female reproductive system produces egg cells in the ovaries, which release an egg roughly once a month; fertilization typically occurs in a fallopian tube, and the resulting embryo implants and develops in the uterus.

The sex of a child is determined by chromosomes. Egg cells carry an X chromosome, while sperm cells carry either an X or a Y. A combination of two X chromosomes generally produces a female, and an X with a Y generally produces a male. After fertilization the single cell divides repeatedly and grows into an embryo, the early stage of development studied in embryology, guided throughout by a balance of reproductive hormones.

Frequently asked questions

What is the function of the testes and ovaries?

The testes produce sperm cells and testosterone, while the ovaries produce egg cells and female hormones. Both make the gametes needed for reproduction.

How is the sex of a baby determined?

It depends on the sex chromosomes from the sperm. An egg always carries an X, so an X-bearing sperm gives a female and a Y-bearing sperm gives a male.

Where does fertilization usually occur?

Fertilization normally takes place in a fallopian tube, where a sperm cell joins an egg. The fertilized egg then travels to the uterus to implant and develop.