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Cognitive ability correlates positively with son birth and predicts cross-cultural variation of the offspring sex ratio

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Abstract

Human populations show remarkable variation in the sex ratio at birth which is believed to be related to the parental condition. In the present study, the global variation of sex ratio at birth (SRB, proportion of male offspring born) was analyzed with respect to indirect measure of condition, the intelligence quotient (IQ). IQ correlates strongly with lifespan across nations, which makes it a good indicator of health of the large populations. Relation between three standard measures of average national IQ and SRB was studied using multiple linear regression models. Average national IQ was positively correlated with SRB (r = 0.54 to 0.57, p < 0.001). Further, IQ emerged as a powerful predictor of SRB after controlling for the effects of all the known covariates like fertility, maternal age, polygyny prevalence, wealth, son preference, latitude, low birth weight, and neonatal mortality in the regression models. These results suggest that the striking variation of offspring sex ratio across nations could be caused in part by the difference in general condition of populations.

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Acknowledgments

Opinions expressed here are solely those of the author and not necessarily of any institute, where the author was employed since the work was started in 2005. I would also disclose that this body of work was conducted at home as a hobby starting from the year 2005. I dedicate this research work to my loving wife Savitri and sweet daughter Adhya (Gubbi) for tolerating my indulgence in this work.

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  1. Madhukar Shivajirao Dama

    Present address: Institute of Wildlife Veterinary Research, KVAFSU, Doddaluvara, Thorenoor post, Somavarpet Taluk, Kodagu District, Karnataka, India, 571232

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  1. S/O: Shivajirao Dama, Atpost: Rajeshwar, Tq: Basavakalyan, Dist, Bidar, Karnataka, India, 585331

    Madhukar Shivajirao Dama

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  1. Madhukar Shivajirao Dama
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Correspondence to Madhukar Shivajirao Dama.

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Communicated by: Sven Thatje

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Supplementary File. 1

Raw data for all the variables used in this study. (XLS 109 kb)

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Dama, M.S. Cognitive ability correlates positively with son birth and predicts cross-cultural variation of the offspring sex ratio. Naturwissenschaften 100, 559–569 (2013). https://doi.org/10.1007/s00114-013-1052-3

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  • DOI: https://doi.org/10.1007/s00114-013-1052-3

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