dating apps and websites. Penile circumcision. Some research suggests that circumcising (removing) the foreskin of the penis can reduce the risk of contracting HIV. Some advocacy groups dispute these findings. Ineffective methods General Most methods of contraception are not effective at preventing the spread of STIs. This includes birth control pills, vasectomy, tubal ligation, periodic abstinence, IUDs and many non-barrier methods of pregnancy prevention. However, condoms, when used correctly, significantly reduces the risks of STI transmission and unwanted pregnancy. The spermicide nonoxynol-9 has been claimed to reduce the likelihood of STI transmission. However, a technical report by the World Health Organization has shown that nonoxynol-9 is an irritant and can produce tiny tears in mucous membranes, which may increase the risk of transmission by offering pathogens more easy points of entry into the system. They reported that nonoxynol-9 lubricant do not have enough spermicide to increase contraceptive effectiveness cautioned they should not be promoted. There is no evidence that spermicidal condoms are better at preventing STD transmission compared to condoms that do not have spermicide. If used properly, spermicidal condoms can prevent pregnancy, but there is still an increased risk that nonoxynyl-9 can irritate the skin, making it more susceptible for infections. The use of a diaphragm or contraceptive sponge provides some women with better protection against certain sexually transmitted diseases, but they are not effective for all STIs. Hormonal methods of preventing pregnancy (such as oral contraceptives [i.e. 'The pill'], depoprogesterone, hormonal IUDs, the vaginal ring, and the patch) offer no protection against STIs. The copper intrauterine device and the hormonal intrauterine device provide an up to 99% protection against pregnancies but no protection against STIs. Women with copper intrauterine device may be subject to greater risk of infection from bacterial infectious such as gonorrhea or chlamydia, although this is debated. Coitus interruptus (or "pulling out"), in which the penis is removed from the vagina, anus, or mouth before ejaculation, may reduce transmission of STIs but still carries significant risk. This is because pre-ejaculate, a fluid that oozes from the penile urethra before ejaculation, may contain STI pathogens. Additionally, the microbes responsible for some diseases, including genital warts and syphilis, can be transmitted through skin-to-skin or mucous membrane contact. Anal sex Unprotected anal penetration is considered a high-risk sexual activity because the thin tissues of the anus and rectum can be easily damaged. Slight injuries can allow the passage