Theoretical and empirical basis for protection by condom
Condoms can be expected to provide different levels of protection for various STDs, depending on differences in how the diseases or infections are transmitted. Male condoms may not cover all infected areas or areas that could become infected. Thus, they are likely to provide greater protection against STDs that are transmitted only by genital fluids (STDs such as gonorrhea, chlamydia, trichomoniasis, and HIV infection) than against infections that are transmitted primarily by skin-to-skin contact, which may or may not infect areas covered by a condom (STDs such as genital herpes, human papillomavirus [HPV] infection, syphilis, and chancroid). As condom is too important in the protection, so you must wear it when has sex.