Humans are sexual, meaning that both a male and a female are needed to reproduce. Each is equipped with specific organs capable of producing specific cells needed to procreate.

In conjunction with a woman’s reproductive organs, sexual intercourse can lead to the reproduction of human life.

For men, the external reproductive organs include:

  • Penis: This tubular, muscular organ fills with blood during arousal, thus making sexual intercourse possible.
  • Scrotum: This pouch-like sac hangs below the penis and encases the testes, or testicles.
  • Testicles: These two oval shaped organs produce sperm cells and testosterone.

While all men are born with all of their sexual organs, they don’t begin to function fully until puberty. The average age of puberty for males is around 12. During this time, hormonal changes affect a boy’s gonads and create lasting changes that have typically been viewed through history as “when a boy becomes a man.” This process has many effects, such as growth in stature, muscular development, and hair growth on the genitals and face.

In terms of reproduction, puberty signals the time when a man has fully-functioning sexual organs and is capable of fathering an offspring.

The male testes produce spermatozoa (more commonly referred to as sperm), which are released at sexual climax, or orgasm. This is known as ejaculation. The sperm leaves the penis in a mixture of secretions designed to nourish and transport the cells into the female reproductive system for procreation.

There are up to 750 million sperm cells contained in a single ejaculation, but it only takes one sperm cell to fertilize a woman’s egg.

The testes also produce the hormone testosterone, which is directly absorbed into the bloodstream. Along with regulating sperm production and maintaining sexual function, testosterone also facilitates common features that physically distinguish men from women, such as facial hair, a deeper voice, more muscle mass, and broader shoulders; these are referred to as “secondary sex characteristics.”

As a man ages, sexual function typically diminishes. Typical sexual abnormalities in men include:

  • Impotence (erectile dysfunction)
  • Sterility
  • Low sperm count
  • Lowered testosterone
  • Premature ejaculation