According to the CDC, although condoms used consistently and correctly can reduce the risk of pregnancy and STIs, they do not offer complete protection. The CDC states “[t]he most reliable ways to avoid transmission of STDs are to abstain from sexual activity, or to be in a long-term mutually monogamous relationship with an uninfected partner.”

When condoms are used consistently (i.e., every time) and correctly (including putting the condom on before intercourse begins), they may:

• Reduce the risk of acquiring STIs that are transmitted by genital fluids, such as chlamydia, and gonorrhea, by 60% and syphilis by 30-50%.
• Reduce the risk of acquiring genital herpes by only about 30% (since it can be passed from the infected skin of one person to the uninfected person and condoms do not cover all the skin of the genital area).
• Reduce the risk of getting HIV during vaginal sex by about 80%.
• Reduce the risk of getting HIV during anal sex by about 70%.
• Reduce the risk for genital human papillomavirus (HPV) infection and HPV-associated diseases (e.g., genital warts and cervical cancer). There is more protection for the areas covered by the condom (condoms do not cover all the skin of the genital area) but even the covered areas are not fully protected. In fact, some studies show little or no risk reduction for HPV infection when using a condom.

It is estimated that condoms are about 85% effective at preventing pregnancy. However, based 2012 study led by Stephanie Sanders of The Kinsey Institute for Research in Sex, Gender, and Reproduction, condoms are often not used consistently and correctly:

• Late application: Between 17 percent and 51.1 percent of people reported putting a condom on after intercourse has already begun – negating the disease-controlling benefits of condom use.
• Early removal: Between 13.6 percent and 44.7 percent of individuals in the studies had taken a condom off before intercourse was over.
• Unrolling a condom before putting it on: Between 2.1 percent and 25.3 percent of people reported completely unrolling a condom before putting it on.
• No space at the tip: Failing to leave a reservoir for semen was reported by between 24.3 percent and 45.7 percent of respondents, depending on the study.
• Failing to remove air: Almost half (48.1 percent) of women and 41.6 percent of men reported sexual encounters in which air wasn’t squeezed from the tip of the condom.
• Inside-out condoms: Between 4 percent and 30.4 percent of people reported rolling on a condom inside out and then flipping it the other way around, potentially exposing their partner to bodily fluids.
• Failing to unroll all the way: 2 percent of women and 8.8 percent of men had started intercourse before a condom was unrolled all the way.
• No lubrication: Between 16 percent and 25.8 percent of participants had used condoms without lubrication, increasing the risk of a break.
• Incorrect withdrawal: Failing to promptly and properly withdraw after ejaculation was a common mistake, occurring in up to 57 percent of encounters in one study.
• Condom reuse: Between 1.4 percent and 3.3 percent of study respondents had re-used a condom at least twice during a sexual encounter.