性行为的基本类型

2. 异性性交: 生殖器性交

性交合注意事项

考虑到当前HIV/AIDS的流行和世界范围其它性传播疾病(STDs)增加的因素，男女都应该要了解与新近偶遇认识的和不熟识的性伴经由阴道性交(性交合)的感染风险。甚至熟识的性伴，如果他们另有偶遇的性伴，那么他们也许不知不觉就已经感染了性传播疾病或艾滋病。对于接受可能受到感染的精液的女子，这种感染的风险更大(换一句话说，这就意味着，妓女冒着经由男性顾客感染的风险比男性顾客经由该妓女感染的风险更大。)男性性伴从感染的阴道分泌液或月经血感染的风险较低，但是也极力建议他们使用安全套。从世界范围来看，阴道性交现在是HIV/AIDS传播的主要途径。

In view of the current HIV/AIDS pandemic and the world-wide increase of other sexually transmitted diseases (STDs), both females and males should understand the risk of infection through vaginal intercourse (coitus) with casual, new, and unfamiliar partners. Even familiar partners may unknowingly have become infected if they, in turn, had casual partners. The risk is greater for the female partners receiving possibly infected semen. (This means, among other things, that female prostitutes run a greater risk of becoming infected through their male customers, than vice versa.) The male partners run a lower risk from infected vaginal fluid or menstrual blood, but they are also well advised to use a condom. World-wide, vaginal intercourse is now the main path of HIV/AIDS transmission.

HIV/AIDS risk
Casual partners may be infected with HIV/AIDS without knowing it. Therefore, unprotected vaginal intercourse with them carries a high risk of infection, especially for the “receiving” partner.
Courtesy BZgA, Cologne