The only sure way to prevent STIs (sexually transmitted infections) is not having any kind of sex. But if you do decide to have sex, take steps to protect yourself. Here's what you need to know.

HPV (human papilloma virus) spreads through skin contact. Some types of HPV cause genital warts. Other types put females at higher risk of cancer of the cervix. HPV is very common in all people. And it can't be cured. But there are treatments to remove warts. Tests can also help spot warning signs of cervical cancer.

HIV weakens the parts of the body that fight off disease (the immune system). It spreads through body fluids passed during sex or through infected needles. When HIV starts to cause severe health problems, it's called AIDS. There's no cure for HIV or AIDS. But treatment called antiretroviral therapy can help you stay healthier longer.

Herpes is a sexually transmitted disease (STD) or sexually transmitted infection (STI). It causes painful outbreaks of blisters and sores. It spreads through contact with an infected area—usually a sore on the genitals, rectum, or mouth.

Hepatitis is a disease that harms the liver through inflammation. Read on to learn more.

Gonorrhea is a sexually transmitted disease (STD) or a sexually transmitted infection (STI). It spreads when body fluids are passed during sex. Infections can occur in the genitals (vaginal sex), anus (anal sex), and throat (oral sex). You may have no symptoms. Or symptoms can be mild to very painful.

Here are answers to common questions about STIs.

Remember: Any kind of sex puts you at risk of sexually transmitted diseases (STDs). Look for signs of STDs on you and your partner. Get checked if you're not sure. And if you do have an STD, get treated! Tell your partner so he or she can get checked, too.

Chlamydia is an STD (sexually transmitted disease) that spreads when body fluids are passed during sex. Signs of chlamydia are often absent or hard to notice. So get checked if you think you might have it. Chlamydia can be cured.

If you're having sex, or thinking about having sex, you need to know about sexually transmitted diseases or STDs. STDs can cause serious health problems. And not all can be cured. But there are ways to protect yourself and others.