无生殖的性行为

人类能够在生命非常早的时期体验到性反应。个体除有其他性活动以外，许多实际的自我性刺激始于青春期之前，并延续至终生。许多人远远超出了其生殖年龄，却仍维持着良好的性行为。有些人则有同性性接触。甚至育龄男女之间的大多数性交不时发生在无怀孕机会的时机。总之：大多数实际的人类性行为不能导致生殖，而且，这已经是始终无可辩驳的事实。

Introduction

Sex without Reproduction

Human beings can experience sexual responses very early in life. Many practice sexual-self-stimulation well before puberty and continue this throughout their lives in addition to any other sexual activity. Most people remain sexually active well beyond their fertile years. Others have same-sex contacts. Even most sexual intercourse between fertile men and women occurs at times when there is no chance of pregnancy. In sum:
Most actual human sexual activity cannot lead to reproduction, and this has always been true.