STD quiz: What you don't know can hurt you

According to the Centers for Disease Control and Prevention (CDC), rates in the United States for many STDs are significantly higher than they were just a few years ago. An estimated 19 million new cases of STDs occur each year in this country, almost half of them in teenagers and young adults, ages 15 to 24.

Although young people are at greatest risk of STDs, they're the least likely to get tested, often because they're embarrassed or because they don't realize they're infected. Many common STDs, such as chlamydia, cause few, if any symptoms, yet they can seriously damage your health and you can unknowingly spread them to others. If you're a sexually active teen or young adult and not in a monogamous relationship, ask your doctor or an STD clinic about being tested. If you're a parent, have frank and open discussions with your children about sex. It could save their lives.

Both body heat and time can lessen the effectiveness of a condom, so it's important not to carry the same one around for a long period of time. Put the condom in your wallet only if you're planning to use it soon — that night or that weekend. If not, keep it in a safe, dry place at home. Also keep an eye on the expiration date listed on the package — never use an expired condom.

Although sperm can't pass through naturally occurring pores in lambskin condoms, disease-causing viruses and bacteria can. Latex condoms offer better protection against sexually transmitted diseases.

Petroleum- or mineral-based lubricants, such as petroleum jelly or baby oil, weaken latex condoms, causing them to tear. If the condom isn't lubricated and lubrication is necessary, use a water-based lubricant, such as K-Y lubricating jelly, on the outside of the condom.

Latex condoms are highly effective — but only when used correctly and consistently. A common cause of condom failure is not leaving space at the tip of the condom. After ejaculation, the lack of sufficient space may cause the condom to tear.

Although uncommon, it's possible to spread the herpes virus when you're not showing signs or symptoms of the disease. And when you have blisters or open sores in your genital area, herpes is highly contagious. Condoms can lower the risk of transmission of the virus, but they don't provide complete protection.

Having a history of genital herpes doesn't mean that you can't have an intimate or sexual relationship, however. To help protect your partner, avoid sex during an active outbreak, use condoms consistently and stick to your medication regimen.

Regular Pap tests can detect — and lead to successful treatment of — abnormal cells before they become cancerous. But Pap tests don't actually prevent you from acquiring the human papillomavirus (HPV) that causes cervical cancer.

HPV is the single most important risk factor for cervical cancer. Your risk of HPV increases with the number of sexual partners you've had — and the number of partners your partners have had. Having first sexual intercourse before age 18 also increases your risk of developing cervical cancer. Pap tests help detect HPV early so you can be treated.

Even if you don't have intercourse, it's possible to get an STD if you engage in unprotected oral sex. The skin-to-skin contact and exchange of body fluids associated with oral sex make it possible for viruses or bacteria to enter your system. For instance, in the case of syphilis or herpes — infections that cause open sores — a person may become infected after direct contact with open sores. The best way to avoid infection is by being in a long-term, mutually monogamous relationship with an uninfected partner.

Birth control pills only protect against unwanted pregnancy — they can't keep you from getting an STD. Condoms are the only form of birth control that protects against STDs as well as unwanted pregnancies. Use a condom in addition to your other method of birth control to reduce your risk of getting an STD.

STDs can be life-threatening; HIV/AIDS is the most devastating example. Despite a slower growth rate of the HIV/AIDS epidemic in developed countries and better medications to slow its toll, AIDS remains a potentially fatal disease with no cure.

According to the CDC, AIDS is the fifth-leading cause of death for people in the United States ages 25 to 44. In the developing world, AIDS is an unprecedented epidemic, killing men, women and children. Worldwide, one child under 15 dies of the disease every minute.

People who share intravenous (IV) needles and those who have multiple sex partners and don't insist on the proper use of condoms remain at highest risk of contracting HIV/AIDS. The best means of battling AIDS is prevention.