A: Although your boyfriend did not ejaculate, he may have released pre-ejaculate (or precum), the clear fluid a man's penis emits when he is sexually aroused. Precum does a lot of useful work; it lubricates the movement of the penis and neutralizes the acidity of any residual urine in the urethra, so that sperm can break on through to the other side. The amount of pre-ejaculate varies from partner to partner, sometimes even going unnoticed by either partner; many men cannot actually feel when it is being released.
Two main factors that influence the likelihood of conception from precum are where you are in your cycle and the sperm count of the pre-ejaculate fluid. The sperm count of precum can vary and is highest if a man has ejaculated recently. For example, if your partner has masturbated before coming over or if you have already caused him to reach orgasm once, the sperm concentration of the precum will likely be higher. Some sperm are just better than others; it is possible that any given batch of precum may have "supersperm" that are more likely to penetrate the egg. We recommend assuming that there may be some sperm contained in pre-ejaculate fluid. It is always safer to use a condom.
Beyond the risk of pregnancy, it is especially important to use a condom to guard against sexually transmitted infections (STIs). The presence of STIs in pre-ejaculate is not a subject of debate. Studies have shown the presence of HIV in pre-ejaculate among those with HIV. Precum coming into contact with your genitals can put you at risk for many sexually transmitted infections because it contains pathogens that can enter the body through sores or microscopic tears in vaginal tissue irritated by friction.
Unprotected contact is risky enough on its own, even without the presence of precum. Human Papilloma Virus (HPV) and herpes can be transmitted through skin-on-skin contact alone. Most HPV infections have no signs or symptoms and therefore most infected persons are unaware that they are infected, yet they can still transmit the virus to a sexual partner. On Amherst's campus, one in four students is infected with HPV.
Penile-vaginal intercourse is not the only time that sexually transmitted infections are a risk. Anal and oral sex should also be protected. Although oral sex is a "lower risk" activity, pathogens can still pass through small cuts along the gum line from partner to partner. In the event that you are performing oral sex without protection, it is suggested that you do not brush your teeth or floss immediately before as this can irritate the gum line and facilitate transmission. Most importantly, when performing oral sex on a man without a condom, it is suggested that partners should not take a man's ejaculate into their mouths.
The best way to protect yourself is to never let things go too far while unprotected. Make sure you are using a condom for any type of genital contact. Allowing "just the tip, just for a second, just to see how it feels" can put you at unnecessary risk for pregnancy and sexually transmitted infections if it is unprotected. Respect yourself, protect yourself!
Please submit your health-related questions and concerns to dmcgoldrick@amherst.edu@amherst.