AIDS, short for Acquired Immune Deficiency Syndrome, is a fatal disease that was first reported in the United States in mid-1981. Now a worldwide epidemic, it's become the number one killer of women between the ages of 20 and 34.

Chlamydia (kluh-MID-ee-uh) is one of the most common sexually transmitted diseases in the United States. An estimated four million people are infected every year.

Genital warts are caused by several types of human papilloma (pap-ih-LOE-muh) viruses, known collectively as H-P-V. The warts appear as growths on the genitals, urethra (yoo-REE-thruh), or cervix, or in the vagina, anus, or throat.

Gonorrhea (gawn-oh-REE-a) remains a common sexually transmitted disease, with approximately two million cases reported in the United States every year.

Herpes (HER-peez) type one causes blisters or cold sores around the mouth, and is not usually acquired by sexual activity. However, genital or type two herpes is most often acquired through sexual intercourse.

Syphilis (SIFF-ih-liss) is a highly contagious disease that can lead to blindness, insanity, or even death, if left untreated. It's transmitted by vaginal and anal intercourse, oral-genital contact, and in a few cases, by kissing, if the organism contacts broken skin.