The penis is an external male sexual organ that is used for urination and sexual intercourse. The testicles are a pair of internal male reproductive organs that produce sperm and testosterone.

The average adult male has genitalia that is about 3-4 inches long and 2 inches in diameter when flaccid. When erect, the average male's genitalia is about 6-8 inches long and 5 inches in diameter.

The shaft of the male genitalia is the main body of the penis. The head of the penis, also called the glans, is the rounded, bulbous end of the penis.

The glans (head) of the penis is typically the most sensitive area and is usually what is stimulated during sexual activity.

The opening at the tip of the head is called the urethral opening and it is through this opening that urine and semen are expelled from the body.

Problems with the male reproductive system can lead to a number of health issues, including infertility, erectile dysfunction, and a low sex drive.

These problems can be caused by a variety of factors, including infection, injury, and congenital defects. Many of these issues can be treated with medication or surgery.