Thanks for your query.
Sexually transmitted diseases are caused by virus that is normally transmitted during intercourse. If one of the partners has any of these diseases, the other person is most likely to get the disease transmitted to him/her. Herpes, AIDS and venereal diseases all come under the category of STDs.
It is totally wrong to say that regular use of birth control pills like Yasmin helps in preventing or treating sexually transmitted diseases. To prevent STDs, it is always advisable to use condoms and not just by popping pills into your mouth.
You should always keep in mind that birth control pills are likely to have many side effects therefore they should not be used on daily basis. They should be taken only under strict medical supervision.
Normally doctors prescribe a high dose of antibiotics to fight an STD because STD is a viral disease. Birth control pills never fight any infection or disease as such. They only take control of the reproductive system.
Remember that it is just a myth and no birth control pill in this world can help in treating or preventing STD.