The reproductive parts of male bodies allow men to enjoy pleasurable sexual feelings, have sexual intercourse and orgasms, and reproduce by making sperm that can fertilize a woman's eggs.

The sexual organs of the male are partly visible and partly hidden within the body. Each part has a medical name and there are lots of other names that people sometimes use.

Penis

The penis hangs outside of a guy's body in the genital area, and underneath the base of the penis is a loose sack of skin that is called the scrotum.

At the top of the penis is an opening called the urethra. Guys pee through the urethra. It is also the hole through which semen spurts out of the guy's penis when he ejaculates during an orgasm.

One of the biggest concerns of many men is the size of their penis. There isn't a right size for a penis at any particular age. Penis size isn't directly related to the ability to bring pleasure to a woman during sexual intercourse. Normally the penis is soft. But when a man gets sexually aroused, blood flows into the penis at a faster rate than it flows out. This makes the penis larger and harder and it is called an erection. The average penis is between 5 and 6 inches long when erect.

Not all erections are caused by sexual excitement. Guys, especially younger guys, can get erections at the weirdest times. These are called spontaneous erections, meaning that they are completely random. This can be embarrassing. However, they go away fairly quickly if you ignore them. Many guys also get erections during their sleep and have a random orgasm in their sleep. This is called a "wet dream" and is completely normal.

Some men are circumcised meaning that the skin which covers the top of the penis (the foreskin) is cut back after birth. Some men are not. Guys who are not circumcised need to pull back the foreskin when they pee or wash themselves.

Scrotum

The scrotum is the loose sack of skin at the base of the penis, in which the testes are hidden. Depending on how cold or warm it is, whether the guy is sexually aroused or not, the scrotum can shrink or expand in size.

Testes

There are two testes (sometimes called "balls") that are inside of the scrotum. The two testes grow in size and become able to produce sperm and male hormones like testosterone. It is best for the testes to be a slightly cooler temperature than the inside of the guy's body. They are very sensitive to injury. When a guy ejaculates, sperm that was made in the testes mixes with other fluids that are made inside the body and spurts out of the penis.Doctors recommend that guys do a Testicular Self Exam once a month to make sure everything is okay. The links below tell you how to do this and what to do if something doesn't seem quite right:

• Testicular Self-Exam
• Examine Yourself

Epididymis

The epididymis is a narrow, tightly-coiled tube connecting the bottom of each testicle to the vas deferens. The epididymis is storage place for the sperm that are made in the testes.

Vas deferens

The vas deferens transports sperm from the epididymis to be ready for ejaculation. During ejaculation, the vas deferens pump sperm towards the penis.

Seminal vesicles

The seminal vesicles produce fluid that mixes with the semen before it is ejaculated.

Prostate gland

The main function of the prostate is to store and release a fluid that makes up about 25-30% of the semen. This fluid combines with the sperm and seminal vesicle fluid. Prostate fluid helps sperm survive and live longer inside the vagina. The prostate contains some smooth muscles that help to pump the semen out of the penis during ejaculation.

There is more helpful information about a man's sexual body parts at the following links.

• Sexuality and U: Male Sexual Organs
• Scarleteen: Male Sexual Anatomy