According to the New England Journal of Medicine, the failure rate of condoms to prevent AIDS is 16.7 percent, while the British Journal of Social Science Medicine says the failure rate can be as high as 31 percent. 2011, a multi-departmental report published by the National Institutes of Health and others said there is no scientific evidence that condoms can prevent most sexually transmitted diseases and examined nine sexually transmitted diseases, including hepatitis B, AIDS, gonorrhea, chlamydia, syphilis, The report also examined nine sexually transmitted diseases, including hepatitis B, AIDS, gonorrhea, chlamydia, syphilis, soft chancre, lymphogranuloma venereum, genital herpes and condyloma acuminata, and found that the condoms currently in widespread use do not prevent the transmission of any of the STDs. Why wear a condom, but also can not prevent the spread of sexually transmitted diseases? 1, condom use incorrect method: improper storage, such as exposure to the sun; condom quality problems; touch sharp objects; inappropriate model, too large or too small; before wearing a condom will not squeeze the air out of the front small sac; vaginal lubrication is poor; use of improper lubricant, weakening the strength of the latex condom; sexual intercourse amplitude is too large. The result of all these reasons is that the condom breaks during intercourse, resulting in direct contact between the sex organs of both men and women, thus increasing the possibility of STD transmission. 2, there is no “airtight” condom condom’s main material is natural latex, its molecular gap between 5000 to 70000 nanometers, if observed under a microscope, condom is just a rubber network. Therefore, although the condom is able to net the head of human sperm with a diameter of about 5,000 nanometers, but, like mycoplasma, chlamydia, bacteria and other very small virus particles that can be seen under a high-powered microscope, the volume is much smaller than the molecular gap of natural latex, such as the diameter of the AIDS virus is only 120 nanometers, hepatitis B virus is 42 nanometers, human papilloma virus in 50 -55 nanometers, far less than 5000 nanometers, very easy to drill through the condom. According to the survey, even if the correct use of condoms, the success rate for the prevention of AIDS is only 84%, the success rate of gonorrhea prevention is only about 56%, and acne vulgaris is almost 0. That is, even if the correct use of condoms, still may be infected with STDs. The actual fact is that you can find a lot of people who are not able to get a good deal on a lot of things. If warts or genital herpes occur on the outside of the labia majora, or if secretions stick to the pubic hair or vulva, STD transmission can occur through contact during sexual intercourse. In fact, preventing the spread of STDs by promoting condom use is not enough, and the results may even be counterproductive. Because some people will think that the use of condoms will not be infected with STDs, thus becoming reckless, but increased the chances of infection. A provincial health department reported the AIDS epidemic in the province in 2010, for example: from January to October 2010, the number of newly discovered HIV infections and patients was 2,062 cases, up 39.3% compared to the same period of the previous year. Therefore, the prevention of STDs should start from personal moral education, cleanliness, establishing correct gender values, maintaining a healthy couple relationship, and eliminating inappropriate sexual behavior are the strongest bulwarks to prevent STDs.