Condoms: extra protection.(CR's Guide To Contraception)

Of the many options available for pregnancy prevention, condoms remain the only method that also can help prevent sexually transmitted diseases, including HIV which causes AIDS.

That's a crucial function: HIV infects 110 Americans each day at least half of them younger than 25. And concerns have evolved over some older sexually transmitted diseases, including gonorrhea, because they have become resistant to the standard drugs used to treat them.

For this report, we evaluated 23 kinds of latex condoms. We also purchased two types made of polyurethane, marketed to people allergic to latex.

Because there's so much confusion over contraceptives, we also created the chart on page 37 with the facts about 17 birth-control methods, so that you can compare them and decide what's best for you. And a report on page 36 details the latest developments in contraception.

In our tests, all latex condoms passed minimum industry standards (no such standards exist for polyurethane models). We found no correlation between performance and price, thickness, or the country of manufacture.

But some models were clearly stronger than others. We rated one model that Planned Parenthood distributes at its clinics as poor because its strength was so low compared with the rest. Here are the details:

Strength differs. We test condoms by inflating them until they burst, an established predictor of real-world performance. The best had no premature breakage among the 120 samples we tested for each model. When inflated, they also averaged at least 38 liters of air. The worst, however, broke 18 of 120 times at volumes below our strength threshold of 25 liters.