The human sex ratio from conception to birth

@article{Orzack2015TheHS,
  title={The human sex ratio from conception to birth},
  author={Steven Hecht Orzack and J. William Stubblefield and Viatcheslav R. Akmaev and Pere Colls and Santiago Munn{\'e} and Thomas Scholl and David Steinsaltz and James E. Zuckerman},
  journal={Proceedings of the National Academy of Sciences},
  year={2015},
  volume={112},
  pages={E2102 - E2111}
}
Significance The human sex ratio has long interested cell biologists, developmental biologists, demographers, epidemiologists, evolutionary biologists, gynecologists, and statisticians. Nonetheless, the trajectory of the human sex ratio from conception to birth has been poorly characterized. We present the most comprehensive analysis of this trajectory ever done. Our dataset is the largest ever assembled to estimate the sex ratio at conception and is the first, to our knowledge, to include data… Expand
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  • S. Austad
  • Biology, Medicine
  • Proceedings of the National Academy of Sciences
  • 2015
TLDR
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Re-examination of Hertig’s data demonstrates that his estimates for fertilisation rate and early embryo loss are highly imprecise and casts doubt on the validity of his numerical analysis. Expand
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TLDR
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TLDR
It is estimated that the heritability for offspring sex ratio was zero, rendering Fisher's principle and several other existing hypotheses untenable as frameworks for understanding human offspring sex ratios. Expand
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References

SHOWING 1-10 OF 314 REFERENCES
Determination of prenatal sex ratio in man
TLDR
The sex of a conceptus at the early embryonic stage was diagnosed in 1000 induced abortions and the sex ratio in the cases of chromosome abnormalities was not statistically different from that of the normal embryos. Expand
[Sex ratio in early embryonal mortality in man].
TLDR
A higher viability of XY embryos during the early stages of ontogenesis in man appears to explain their underrepresentation in samples of spontaneously aborted embryos and appears to be the major factor responsible for the deviation of the sex ratio from the theoretically expected value. Expand
Sex ratio of human conceptuses.
TLDR
The results suggest that higher mortality of male versus female conceptuses is restricted to the period of organogenesis, and seasonal or monthly variation in the sex ratio was not found. Expand
Gender aspects of preterm birth
  • I. Ingemarsson
  • Medicine
  • BJOG : an international journal of obstetrics and gynaecology
  • 2003
TLDR
Gender differences in mode of delivery, fetal heart rate in labour, acidaemia at birth, and age degenerative changes will also be discussed. Expand
Sex ratio among human embryos and newborns in a Russian population
TLDR
It was calculated that more precise determination of the sex ratio in the embryonal period would require the study of not less than 17 500 embryos, and the confidence limits are presented for the significance of possible differences in the sex ratios in samples ranging from 100 to 500000 in size. Expand
Sex ratio in human embryos obtained from induced abortion: histological examination of the gonad in 1,452 cases.
TLDR
In this histological analysis of 1452 human embryonal gonads on a large scale, embryos were obtained from mothers whose pregnancies were interrupted by curretage mainly for social reasons, it may be conceivable that the earlier the gestational stage, the higher the sex ratio of conceptuses. Expand
The sex ratio before uterine implantation in the golden hamster.
  • G. Sundell
  • Biology, Medicine
  • Journal of embryology and experimental morphology
  • 1962
The primary sex ratio in mammals, i.e. the proportion of males to females at the time of fertilization, has been estimated in previous studies exclusively on the basis of the sex distribution ofExpand
Fetal sex and preterm birth: are males at greater risk?
BACKGROUND The existence of a male excess among preterm births is interesting because it could shed light on the aetiology of preterm birth. Possible mechanisms are greater body weight, increasedExpand
Trisomy 18: Changes in sex ratio during intrauterine life
TLDR
This study included not only the prenatally examined cases but also the postnatally detected cases (spontaneous abortions, stillborns, and live-borns) in whom the gestational age at birth was known in order not to miss sex differences in the third trimester of pregnancy. Expand
Sex ratio is remarkably constant.
TLDR
Sex ratio at birth is remarkably constant and no association was found between parental age or birth order and neonatal sex ratio. Expand
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