The hymen, a membrane covering the external opening of the vagina, is usually present in girls or women until something--like penetrative sex or masturbation--has ruptured it. During a gynecological exam, a doctor would be able to see whether or not a girl has a hymen. But lack of a hymen alone does not necessarily indicate that intercourse has occurred. Some girls and women rupture their hymens during jostling sports like horseback riding, for example.

My question is whether you are trying to hide the fact that you are sexually active from your gynecologist. This information is important for your gynecological health care provider to know. If you would like the information kept confidential, most practitioners would be happy to respect your privacy. Ask about your doctor's policy on confidentiality, but it's probably in your best interest not to withhold this information.