最近几十年来,世界人口有了较快的增长,1920年世界人口祗有十八亿六千二百万,到了1970年增长至三十六亿三千二百万,几乎增加了一倍,据估计若按目前每年以2％的增长率继续增长的话,到了公元2000年,世界总人口将达七十亿。由于人们越来越深刻地认识到不能无控制地使人口增长,因而促进了人类生殖生理方面的研究,许多国家都在纷纷制订自己的政策,推行计 In recent decades, the world population has witnessed a rapid growth. In 1920, the world’s population was only 1.862 billion. By 1970, it had grown to 3.362 billion and nearly doubled. It is estimated that by the current 2% annual growth rate will continue to grow by the year 2000, the world’s total population will reach 7 billion. As more and more people realize that they can not increase their population uncontrollably, thus promoting the study of human reproductive physiology, many countries are formulating their own policies and implementing plans