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决定胎儿性别有 X、Y 两种精子,其重量不同,利用其重量的差别将二者分离后可以按父母的希望选择性别生产男儿或女儿。庆应大学医学部饭冢理八教授研究组已成功地按计划使6例母亲生产了女婴。但是不加限制地施行这个方法将使人口性别比例发生变动,今后包括生命伦理领域在内,可能引起一场大争论。婴儿性别决定于性染色体的组合。卵子只含有 X染色体,而精液中有含有 X 染色体的 X 精子和含有 Y染色体的 Y 精子。受精卵和 X 精子结合则婴儿为女性;和 Y 精子结合则婴儿为男性。精液中一半为 X 精子,一半为 Y 精子,若选择性别生产必需把这两种精子加以分离。Y 染色体比 X 染色体小,所以它比 X 染色体略轻。过去是利用这个重量差异经过离心机分离。
Fetal sex determination of X, Y two sperm, its weight is different, the use of its weight difference between the two separated according to the parents hope that the choice of gender production of men or daughters. Graduate School of Medicine, Keio University Professor Iizuka Ka-8, Keio University, has succeeded in producing 6 males as planned. However, unrestricted implementation of this method will lead to a change in the sex ratio of the population, and future bioethical areas may cause a big argument. Baby sex is determined by the combination of sex chromosomes. The egg contains only the X chromosome, while the semen contains the X chromosome X chromosome and the Y chromosome Y chromosome. When combined with fertilized egg and X-sperm, the baby is female; in combination with Y-sperm, the baby is male. Semen half of X sperm, half of Y sperm, if the choice of sex production must be separated from the two sperm. The Y chromosome is smaller than the X chromosome so it is slightly lighter than the X chromosome. The past is to use this weight difference through the centrifuge separation.