1.    Are condoms effective at preventing pregnancy?

Yes, male condoms are effective, but only if used correctly with every act of sex. When used consistently and correctly, only 2 of every 100 women whose partners use condoms become pregnant over the first year of use. Many people, however, do not use condoms every time they have sex or do not use them correctly. This reduces protection from pregnancy.

2.    How well do condoms help protect against HIV infection?

On average, condoms are 80% to 95% effective in protecting people from HIV infection when used correctly with every act of sex. This means that condom use prevents 80% to 95% of HIV transmissions that would have occurred without condoms. (It does not mean that 5% to 20% of condom users will become infected with HIV.) For example, among 10,000 uninfected women whose partners have HIV, if each couple has vaginal sex just once and has no additional risk factors for infection, on average:

• If all 10,000 did not use condoms, about 10 women would likely become infected with HIV.
• If all 10,000 used condoms correctly, 1 or 2 women would likely become infected with HIV.

The chances that a person who is exposed to HIV will become infected can vary greatly. These chances depend on the partner's stage of HIV infection (early and late stages are more infectious), whether the person exposed has other STIs (increases susceptibility), male circumcision status (uncircumcised men are more likely to become infected with HIV), and pregnancy (women who are pregnant may be at higher risk of infection), among other factors. On average, women face twice the risk of infection, if exposed, that men do.

3.    Does using a condom only some of the time offer any protection from STIs, including HIV?

For best protection, a condom should be used with every act of sex. In some cases, however, occasional use can be protective. For example, if a person has a regular, faithful partner and has one act of sex outside of the relationship, using a condom for that one act can be very protective. For people who are exposed frequently to STIs, including HIV, however, using a condom only some of the time will offer limited protection.

4.    Will using condoms reduce the risk of STI transmission during anal sex?

Yes. STIs can be passed from one person to another during any sex act that inserts the penis into any part of another person's body (penetration). Some sex acts are riskier than others. For example, the risk of becoming infected with HIV is 5 times higher with unprotected receptive anal sex than with unprotected receptive vaginal sex. When using a latex condom for anal sex, a water- or silicone-based lubricant is essential to help keep the condom from breaking.

5.    Are plastic (synthetic) condoms effective for preventing STIs, including HIV?

Yes. Plastic condoms are expected to provide the same protection as latex condoms, but they have not been studied as thoroughly. Condoms made of animal membrane such as lambskin condoms (also called natural skin condoms) are not effective for preventing STIs, including HIV.

6.    Do condoms often break or slip off during sex?

No. On average, about 2% of condoms break or slip off completely during sex, primarily because they are used incorrectly. Used properly, condoms seldom break. In some studies with higher breakage rates, often a few users experienced most of the breakage in the entire study. Other studies also suggest that, while most people use condoms correctly, there are a few who consistently misuse condoms, which leads to breaks or slips. Thus, it is important to teach people the right way to open, put on, and take off condoms (see Explaining How to Use Male Condoms) and also to avoid practices that increase the risk of breakage (see What Condom Users Should Not Do).

7.    What can men and women do to reduce the risk of pregnancy and STIs if a condom slips or breaks during sex?

If a condom slips or breaks, taking emergency contraceptive pills can reduce the risk that a woman will become pregnant (see Chapter 3 – Emergency Contraceptive Pills). If exposure to HIV is likely, treatment with antiretroviral medications (post-exposure prophylaxis), where available, can help reduce HIV transmission. If exposure to other STIs is likely, a provider can treat presumptively for those STIs—that is, treat the client as if he or she were infected.

Washing the penis does not help prevent STIs. Vaginal douching is not very effective in preventing pregnancy, and it increases a woman’s risk of acquiring STIs, including HIV, and pelvic inflammatory disease.

8.    Can a man put 2 or 3 condoms on at once for more protection?

There is little evidence for the benefits of using 2 or more condoms. It is generally not recommended because of concerns that friction between the condoms could increase the chance of breakage.

9.    Will condoms make a man unable to have an erection (impotent)?

No, not for most men. Impotence has many causes. Some causes are physical, some are emotional. Condoms themselves do not cause impotence. A few men may have problems keeping an erection when using condoms, however. Other men—especially older men—may have difficulty keeping an erection because condoms can dull the sensation of having sex. Using more lubrication may help increase sensation for men using condoms.

10.  Aren't condoms used mainly in casual relationships or by people who have sex for money?

No. While many casual partners rely on condoms for STI protection, married couples all over the world use condoms for pregnancy protection, too. In Japan, for example, about 40% of married couples use condoms—more than any other family planning method. 

11.  Is allergy to latex common?

No. Allergy to latex is uncommon in the general population, and reports of mild allergic reactions to condoms are very rare. Severe allergic reactions to condoms are extremely rare.

People who have an allergic reaction to rubber gloves or balloons may have a similar reaction to latex condoms. A mild reaction involves redness, itching, rash, or swelling of the skin that comes in contact with latex rubber. A severe reaction involves hives or rash over much of the body, dizziness, difficulty breathing, or loss of consciousness after coming in contact with latex. Both men and women can be allergic to latex and latex condoms.