20世纪,是人口爆炸的世纪。世界人口已由19世纪初的10亿增长到目前的50亿。人口爆炸与盲目的生育不无关系,科学家为了控制人口做了许多最实际的,工作。避孕药之所以在这个世纪发现,而不是较早的什么时候,可以说既是奇迹又属必然。 30年代后期美国宾夕法尼亚大学教授马克尔在墨西哥野生的薯类植物中发现一组类固醉物质,并对此产生很大兴趣。经研究他发现, The twentieth century is a century of population explosion. The world population has risen from one billion in the early nineteenth century to the present five billion. Population explosion and blind birth are not unrelated, scientists in order to control the population to do the most practical work. The reason why birth control pills are discovered in this century, rather than earlier, is both a miracle and a necessity. In the late 1930s, Markel, a professor at the University of Pennsylvania, found a group of cannabinoid substances in wild potato plants in Mexico and was very interested in this. After studying he found,