绪论

性与生殖

人类通过有性生殖繁殖，也就是通过男女特殊的性交形式产生后代。男女性器官能够容易地交接，而且如果男女双方达到性成熟，这种交接（称为交配或交媾）为女性的性细胞（卵子）和男性的性细胞（精子）的融合提供了机会。这种融合产生了可以在女性体内发育成新的人类个体的新细胞。

Egg and sperm cells 正在弱化的链接 从前，在男女之间的人类生殖与性交非常紧密地铰链在一起。但是，现代科学已经松解了这根链条，现今，有性交而无生殖和有生殖而无性交比以往变得更加容易。 A weakening link Human reproduction and sexual intercourse between women and men were very closely linked in the past. However, modern science has loosened the connection, and today it is easier than ever before to have sexual intercourse without reproducing and to reproduce without sexual intercourse.

Introduction

Sex and Reproduction

Human life is reproduced sexually, i.e. through a special form of sexual intercourse between women and men. The sex organs of females and males can easily be joined together, and, if they are sexually mature, such a joining (called copulation or coitus) provides an opportunity for the female sex cell (egg) and one male sex cell (sperm) to unite. This union results in a new cell which may grow inside the woman into a new human being.