Variation in the sex-ratio at birth
An analysis of the data concerning 1371 hospital offspring population in South India does not indicate any evidence that the determination of sex in the sample is not a chance factor. It revealed that the secondary sex-ratio is neither influenced by the degree of the fathers physical labour (rated from the fathers occupation), nor by the maternal age. The sex-ratio showed a significant association with the seasonality of birth and the birth order.
KeywordsBirth Order Physical Labour Male Birth Selective Mortality Chance Factor
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- Bernstein, M. E. and Martinez-Gustin, M. M. (1961). Physical and psychological variation and the sex-ratio.J. Hered. 52, 109.Google Scholar
- Ciocco, A. (1938). Variation in the sex ratio at birth in the United States.Hum. Biol. 10, 36.Google Scholar
- Crew, F. A. E. (1932). The Sex Ratio. InEncyclopaedia Brittannica. 14th Ed. Vol. 20. p. 415.Google Scholar
- Hoelzel, F., Da Costa, E. and Carlson, A. J. (1939). Effect of protein alimentation on the secondary sex ratio of offsprings of rats.Proc. Soc. Exp. Biol. 40, 334.Google Scholar
- Jalavisto, E. (1952). Sex ratio at birth and its dependence on birth order and parental age.Ann. Chir. Gyn. Fenniae,40, 129.Google Scholar
- Kang, Y. S. and Cho, W. K. (1959). The sex ratio at birth of the Korean population.Eugen. Quart. 6, 187.Google Scholar
- Lewis, C. J. and Lewis, J. N. (1906). Natality and fecundity.Oliver and Boyd, London.Google Scholar
- McMahon, B. and Pugh, T. F. (1953). Influence of birth order and maternal age on the human sex ratio at birth.Brit. J. Prev. Soc. Med. 7, 83.Google Scholar
- Novitsky, E. and Kimball, A. W. (1958). Birth order, parental ages and sex of offsprings.Amer. J. Hum. Genet. 10, 268.Google Scholar
- Parkes, A. S. (1926). The mammalian sex ratio.Biol. Rev. 2, 1.Google Scholar
- Savorgnan, F. (1933). La statistica della nascite legittime secondo l'ordine di generazione. Rome, Instituto Poligrafigo dello Stato.Google Scholar
- Stern, C. (1960). Principles of Human Genetics. San Francisco,Freeman.Google Scholar