Quiz: How Much Do You Know About STDs?

Genital herpes, like other sexually transmitted diseases (STDs), is spread by vaginal, oral, or anal sex. The virus that causes it can't live for long outside the body, so you can't catch it from an object like a toilet seat or towel. Oral herpes is spread by saliva, usually during kissing or oral sex.

It may sound super-safe, but wearing two condoms doesn't double your protection. Instead, they can rub against each other, causing friction. That can make the condoms break or tear, which means you're not protected at all.

You might notice a rash, sores, or redness down there -- or not. People with STDs don't always have symptoms. You can't know for sure unless you're tested.

About half of all new STD cases are in people ages 15 to 24. The younger you start to have sex, the more likely you’ll end up with an STD. But anyone can get one -- especially if you have unprotected sex with more than one partner.

Saliva spreads the virus that causes oral herpes. So there's a chance it can be passed by glasses, straws, utensils, or lip balm. Don't share these, especially if you or your partner has cold sores or blisters.

Birth control pills can't stop STDs. Condoms are the best way to help prevent them. Use a latex condom every time you have vaginal, oral, or anal sex. Birth control cream, foam, or jelly, too, may also kill some STD germs. Use them with a condom, not instead of one.

Not really. It means the STD wasn't in your body at the time of the test. Infections caused by a virus -- like herpes, HPV, and HIV -- can take as long as 3 months to show up after you've been exposed. A follow-up test in 3 more months will let you know for sure.

Doctors can cure some STDs, like gonorrhea and chlamydia, with medication. Others, like herpes and HIV, stay with you forever, but there's medicine to help your symptoms. Treatment also helps stop STDs from causing you further health problems.

You can pass around bacteria and diseases if you don't clean your bedroom toys and you share them with your partner. After each use, wash items in warm, soapy water. Rinse well.

Genital human papillomavirus (HPV) is the most common sexually transmitted infection in the U.S. It's spread through vaginal, anal, or oral sex. You can get it even if your partner doesn’t show symptoms. There are many types of HPV. Some cause genital warts. Others lead to cancer. It's important to note, too, that there is a vaccination that prevents most HPV associated with cervical cancer. You can lower your chances of problems by using condoms, getting Pap smears, and through vaccinations.