Hi Dr. Kate,

My boyfriend is a virgin, and I'm...not. I've always used protection with previous sexual partners, and I got tested for STD's after my last encounter. Last weekend he wanted to have sex, but didn't have condoms. I'm on the NuvaRing, but I made up an excuse and told him I didn't trust my birth control. My real reason was I was afraid to pass on STD's to him that I wasn't aware of carrying (even though I'm clean). I know that it's possible to transfer STD's to your partner when you show no symptoms (like herpes and warts). My question is, if I theoretically didn't use condoms with him(I think I still will use protection with him, I already bought us a box), how likely am I to pass on something to him?

The (possibly) dirty devirginizer

Dear (P)DD,

How considerate of you! First thing is to assess your chances of actually having an STD to pass. Gynos can test you for the following infections:

• chlamydia and gonorrhea (during your pelvic exam or with a urine sample)
• trichomoniasis (also with a pelvic)
• HIV (generally a blood test, though sometimes a finger stick or a cheek swab)
• syphilis and hepatitis (blood tests)
• HPV (during your pap smear)--we can't directly test you for warts

Herpes testing is tricky, and the best way to know for sure if you have genital herpes is to swab a bump during an outbreak. If you were tested for all of the other infections after your last encounter (and to be safest, six months after, to allow time for any tests to become positive), that gives you great peace of mind.

If you've never had an outbreak of warts or herpes, your chances are low of not having either one. Not zero chances, but lower. These two infections, unfortunately, are also the ones most likely spread even when using a condom...or by "outercourse" (which may mean that your boyfriend has been at risk as well, depending on what you mean by "virgin"). So what is the chance of passing an infection that you don't know you have? It's not high, but I can't say how low. While most infections with warts or herpes lead to an outbreak in the first several weeks of exposure, we don't know how common it is to not have your first outbreak for months or even years after infection (it's a hard thing to study).

Unfortunately, sex always entails a certain degree of risk--emotional and physical. Using condoms certainly lowers the physical risks, and gives you the best peace of mind. How often do you all use condoms during sex?