False. According to the World Health Organization there are at least 30 types of bacteria and viruses that are sexually transmitted. Of those 30, 8 account for the majority of STIs and 4 of them are incurable, meaning that doctors can typically treat the symptoms but cannot remove the underlying cause. Cases of other STIs (gonorrhoea, chlamydia, syphillis, trichomoniasis) has become increasingly difficult due to antibiotic resistance.