S EXUALLY TRANSMITTED DISEASES (STDs) are a group of infectious diseases that are passed from person to person primarily by sexual contact. More than twenty diseases are classified as STDs.

Their symptoms vary, their severity and effects vary, and they are caused by varied kinds of organisms, so no one description fits all STDs.

It is important to understand that though most STDs involve the genitals, the symptoms and effects of STDs can occur anywhere in the body. Similarly, the appearance of symptoms in the genital area does not automatically indicate infection by an STD. There are many other diseases that affect the genitals, from bacterial infections to cancer, that are not classified as STDs because they are not transmitted through sexual contact.

Besides their common method of transmission, STDs have another important feature in common...