Separation of human X and Y spermatozoa by albumin gradients and Sephadex chromatography. Quinlivan WLG, Preciado K, Long TL, Sullivan H. Isolation of fractions rich in human Y sperm. BMJ 1997 315:1386.Įricsson RJ, Langevin CN, Nishino M. J Gynecol Obstet Biol Reprod (Paris) 1975 4:145–149.Ībbasi K. Value for the prevention of sex-linked malformations and of certain recurrent abortions. Methods of natural and voluntary sex selection. Results of a 2 years’ prospective clinical study. Preconceptional selection of sex using the ionic method. Effect of sexual abstinence on the proportion of X-bearing sperm as assessed by multicolor fluorescent in situ hybridization. Hilsenrath RE, Swarup M, Bischoff FZ, et al. Thorsons Publications Ltd, Northamptonshire, UK, 1985. Effect on the probability of conception, survival of the pregnancy, and sex of the baby. Timing of sexual intercourse in relation to ovulation. This process is experimental and the keywords may be updated as the learning algorithm improves. These keywords were added by machine and not by the authors. Because the human sex ratio is almost 50:50, it appears that the sex ratio of babies born primarily reflects the ratio of X- and Y-bearing sperm in semen and is probably not significantly impacted by other factors, such as the female reproductive tract environment or differential fetal survival to birth. The mechanisms of meiosis in the production of gametes by the heterogametic parent should, in theory, yield an equal number of male and female offspring. For humans, the male is the heterogametic parent, producing both X and Y chromosome-bearing sperm. Chromosomal sex is determined at fertilization by the heterogametic parent. Different cultures, social classes, and races may exhibit different preferences for a child of a given sex. The mechanisms and possibilities of controlling or predetermining the sex of offspring are likely to have been pondered by humans throughout history.
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