First off, if there's a sore on your penis, your vulva, or your asshole, or you have some mysterious burning sensation down there somewhere, GO SEE A GODDAMNED DOCTOR. (There's a list of STD clinics in the map at the center of this issue.) Don't just sit there in your dorm hoping it goes away--because some sexually transmitted diseases will do just that. You'll show some symptoms at first--a sore, a burning sensation, a sudden appreciation for emo--and then just as suddenly your symptoms will clear up. But you're not necessarily disease-free, kiddo. Your STD may just be laying low, hanging out in your body, infecting other people you have sex with, and biding its time until it roars back to life, makes you go blind or insane, gives you cervical cancer, sterilizes you, or makes your dick fall off.

Seriously, guys, your dicks can fall off.* So go see a doctor if you suspect you have an STD or two years later you'll be a dickless loser.

Here's a brief rundown of the various STDs you're likely to encounter/contract/ avoid during your college career.

CHLAMYDIA The most common STD among college-age men and women. It's caused by a bacterium, which left untreated can cause pelvic inflammatory disease, which can lead to infertility in men and women. Most people show no symptoms, which is why it's important for sexually active young adults to get regular STD screenings.

GENITAL WARTS They're like warts--but on your dick, balls, ass, vagina--and are sometimes deep inside your ass or vagina, where you can't see 'em. Here's the good news about the wart-causing human papillomavirus: In most cases, your own immune system will cause most of the warts to disappear after about six months, and your body will no longer harbor the virus. Still, you'll want to get any warts you can see removed--burned off, in most cases--and women should get regular pap smears to make sure they don't have any warts deep inside, which can lead to cervical cancer later in life.

HERPES Before AIDS came along and put herpes in perspective, people regarded herpes as the worst thing that could possibly happen to you. Nowadays folks are likelier to regard herpes (type 1 causes small blisters on your mouth; type 2 gives you small sores on your genitals) as an endurable pain, not a lifelong curse. Millions of people who "have" herpes show no symptoms and suffer no regular outbreaks. There's no cure, but there are treatments that can suppress outbreaks.

GONORRHEA Burning sensation when you pee? Pussy discharge? Go to the damn doctor: There's a cure for this bacteria-induced STD. Some people with gonorrhea show no symptoms, so sexually active folks should get regular STD screenings.

SYPHILIS If you spot a small sore or rash on your genitals, GO TO THE DOCTOR. It could be syphilis, which is treatable--completely curable. Left untreated, however, syphilis leads to blindness, insanity, and death.

AIDS The HIV virus tears up your body's immune system and leads to AIDS, AKA acquired immune deficiency syndrome. There are effective treatments for HIV today, but they're complicated, have side effects, and are expensive.

Now for the good news: Using condoms offers a great deal of protection from all of the STDs listed above. If you're relatively choosy about who you have sex with (one member of the football team at a time, thanks) and how you have sex with them (condoms, low-risk sex options like oral or mutual masturbation), you won't have to worry about most STDs.

Now the bad news: Using condoms does not offer 100 percent protection, and you can be choosy and use condoms and still get an STD. If you get an STD, don't beat yourself up; just head to the doctor or STD clinic. Rest assured, you're not a diseased slut; by age 24, one in three sexually active people will contract an STD, so you're in good company. Having an STD doesn't make you a bad person; it's how you behave once you know you have an STD that makes you good or bad. If you seek treatment, refrain from having sex with anyone while you're still infectious, or (if we're talking herpes or HIV) inform your sex partners that they're running some slight risk of contracting these STDs when they sleep with you, well, then you're a good person. If, on the other hand, you don't get treated, fuck other people without any regard for their health or safety, and spread your STD around, well, then should feel like a bad person because you are a bad person.

*People's dicks don't fall off, of course. But only the threat of having their dicks fall off will prompt some college-age boys to go to the doctor.