heterosexual couples may use oral or anal sex (or both) as a means of birth control. However, pregnancy can still occur with anal sex or other forms of sexual activity if the penis is near the vagina (such as during intercrural sex or other genital-genital rubbing) and its sperm is deposited near the vagina's entrance and travels along the vagina's lubricating fluids; the risk of pregnancy can also occur without the penis being near the vagina because sperm may be transported to the vaginal opening by the vagina coming in contact with fingers or other non-genital body parts that have come in contact with semen. Safe sex is a relevant harm reduction philosophy and condoms are used as a form of safe sex and contraception. Condoms are widely recommended for the prevention of sexually transmitted infections (STIs). According to reports by the National Institutes of Health (NIH) and World Health Organization (WHO), correct and consistent use of latex condoms reduces the risk of HIV/AIDS transmission by approximately 85–99% relative to risk when unprotected. Condoms are rarely used for oral sex and there is significantly less research on behaviors with regard to condom use for anal and oral sex. The most effective way to avoid sexually transmitted infections is to abstain from sexual intercourse, especially vaginal, anal, and oral sexual intercourse. Decisions and options concerning birth control can be affected by cultural reasons, such as religion, gender roles or folklore. In the predominantly Catholic countries Ireland, Italy and the Philippines, fertility awareness and the rhythm method are emphasized while disapproval is expressed with regard to other contraceptive methods. Worldwide, sterilization is a more common birth control method, and use of the intrauterine device (IUD) is the most common and effective way of reversible contraception. Conception and contraception are additionally a life-and-death situation in developing countries, where one in three women give birth before age 20; however, 90% of unsafe abortions in these countries could be prevented by effective contraception use. The National Survey of Sexual Health and Behavior (NSSHB) indicated in 2010 that "1 of 4 acts of vaginal intercourse are condom-protected in the U.S. (1 in 3 among singles)," that "condom use is higher among black and Hispanic Americans than among white Americans and those from other racial groups," and that "adults using a condom for intercourse were just as likely to rate the sexual extent positively in terms of