But, although the risk may be minuscule, it might still be something to take into consideration. Chlamydia is incredibly common among the college age population and it is usually asymptomatic. If untreated, it could lead to sterilization for both men and women. This virus can be transmitted by oral sex when one person is infectious, or by contact with a blister on one's mouth and then touching someone's genitals with that hand. And, herpes can be transmitted when a sore is not yet present or active.
Condoms are the number one method of birth control, for all the reasons listed above.