英《泰晤士报》1980年1月30日科学报告栏报道:过去已认识到妇女在35岁以上妊娠,胎儿染色体过多的机会增加。现在几个国家的报告表明年轻妇女,多数在25岁以下怀孕的胎儿,很有可能缺少一个染色体。有问题的胚胎缺少两个性染色体中的一个,不是有两个X染色体或一个X和一个Y染色体,而是只有一个X染色体,即所谓45个XO The Times The Times reported January 30, 1980 in the Science Bulletin: In the past, women had been aware that when they were over 35 years of age, there was an increased chance of having an excess of fetal chromosomes. Several countries now report that young women, most of whom are pregnant under 25, are most likely to lack a chromosome. The defective embryo lacks one of the two sex chromosomes, instead of having two X or one X and one Y chromosome, but only one X chromosome, the so-called 45 XO