性交可以是人的一生中最健康和最令人愉快的體驗。不幸的是，它有時也被認為是痛苦、苦楚甚至死亡的根源。有一個戲劇性的事例就是通過性接觸接連地傳播危險的傳染病。自從通過適當的預防，這種傳染病能夠容易地避免後，這就尤其使人感到煩惱了。至少，這些通過性接觸的傳染病中有一種病（乙型肝炎）是能夠通過接種疫苗而預防的，其他的這類疾病則通過“安全”性行為也能夠被預防的。一些人在性的方面能夠堅持禁欲並且由此規避所有的風險。另有一些人一生維持僅有的一個性伴的專一性關係。儘管如此，這個性伴可能秘密地有了其他的性接觸。真實的情形是，非常多的男男女女既不禁欲也不性專一。就這些事例來說，堅持“安全性行為”習慣，或至少一貫和正確使用避孕套（安全套）能夠提供安全保護。

可是，因為多種多樣的原因，許多人未能使用任何保護措施。一些人有個人的禁忌，但是也可能有客觀的阻礙：許多男男女女們未獲得該享有的有關預防性傳播疾病的知識教育或者被誤導，另一些人們不能得到性傳播疾病的檢測和不能獲得醫學治療。對某些人來說，安全套仍然太貴，或者獲得安全套有困難，甚至難以獲得它們。最後，在某些社會裏，只要男性拒絕合作，女性在保護自身方面仍顯得無能為力。所以，性傳播疾病不僅是一個醫學疾病，而且是一個很大的社會、文化、甚至政治問題。

Sexual intercourse can be among the healthiest and most enjoyable experiences in life. Unfortunately, it is also sometimes allowed to become the source of misery, suffering, and even death. One dramatic example is the continuing spread of dangerous infections through sexual contact. This is especially disturbing since, with appropriate precautions, such infections can easily be avoided. At least one of them can be prevented by vaccination (Hepatitis B) and the others by “safe” sexual behavior. Some people are able to remain sexually abstinent and thus escape all risks. Others live in an exclusive relationship with only one partner. Still, the partner may secretly have other sexual contacts. Indeed, very many females and males are neither abstinent nor sexually exclusive. In these cases, the practice of “safer sex”, or at least the consistent and correct use of a condom, can provide protection.

However, for a variety of reasons, many people fail to use any protection. Some have personal inhibitions, but there may also be objective obstacles: Many women and men are uninformed or misinformed about the STDs and their prevention, others cannot get tested and cannot get medical treatment. For still others, condoms are too expensive, or they are difficult to get or even unavailable. Finally, in some societies, females are kept powerless to protect themselves as long as the males refuse to cooperate. Therefore, STDs are not only a medical, but also a larger social and cultural, indeed, a political problem.