Which contraceptive can provide a dual function of preventing pregnancy and sexually transmitted infections?

The condom stands out as the only contraceptive option that offers dual protection against both pregnancy and sexually transmitted infections (STIs). When used properly, condoms create a physical barrier that prevents sperm from reaching the egg, thereby effectively preventing pregnancy. Simultaneously, this barrier also protects against the exchange of bodily fluids, reducing the risk of transmission of infections such as HIV, chlamydia, and gonorrhea.

Other contraceptive methods, like birth control pills, IUDs, and sponges, primarily focus on preventing pregnancy but do not provide protection against STIs. Birth control pills regulate hormones to inhibit ovulation, IUDs alter the uterine environment to prevent fertilization, and sponges block sperm entrance to the uterus, but none of these methods prevent the transmission of infections between partners. Therefore, the condom is unique in its ability to serve both functions effectively.