"When the birth control pill took over as the main form of contraception for women, it replaced a variety of other methods, all of which acted as a barrier to sperm reaching an egg for fertilisation. But these methods did more than prevent sperm getting through, they also prevented diseases from entering the reproductive organs. Today, many women have had more than one sexual partner and there has been a dramatic increase in sexually transmitted disease (STDs). Some of the classic STDs, such as syphilis, are in decline (the result of early detection and improved methods of treatment), but they have been replaced by another group of infectious agents, which can cause discomfort and more serious problems..."