Does the Mother or Father Determine the Offspring Sex Ratio? Investigating the Relationship between Maternal Digit Ratio and Offspring Sex Ratio

AbstractThis article explores how family structure and domicility influences offspring sex ratio bias, specifically living arrangements of husband in polygynous unions. Data from three Ghana Demographic and Health Surveys were used to examine the relationship between family structure and offspring sex ratio at birth, something that previous studies have not been able to do. This study estimate models of sex ratio offspring if the wives live together with husband present and wives live in separate dwellings and are visited by husband in turn. The results suggest that within polygynous marriages there are more male births, especially when husbands reside in the same dwelling as wives, than when husbands reside in separate dwellings from their wives. The analyses show that offspring sex ratio is related to the structure of living arrangement of husbands in polygynous unions. Indeed, the findings suggest that living arrangements and family structure among humans are important factors in predicting offspring sex ratio bias.

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The Relationship Between Offspring Sex Ratio and Vasectomy Utilization

Urology ◽

10.1016/j.urology.2016.11.039 ◽

2017 ◽

Vol 103 ◽

pp. 112-116 ◽

Cited By ~ 1

Author(s):

Remy W. Lamberts ◽

David P. Guo ◽

Shufeng Li ◽

Michael L. Eisenberg

Keyword(s):

Sex Ratio ◽

Offspring Sex Ratio ◽

Offspring Sex ◽

The Relationship

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Maternal 2nd to 4th digit ratio does not predict lifetime offspring sex ratio at birth

American Journal of Human Biology ◽

10.1002/ajhb.20796 ◽

2008 ◽

Vol 20 (6) ◽

pp. 700-703 ◽

Cited By ~ 10

Author(s):

Samuli Helle ◽

Thomas Lilley

Keyword(s):

Sex Ratio ◽

Digit Ratio ◽

Sex Ratio At Birth ◽

Offspring Sex Ratio ◽

Offspring Sex

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Covariance of paternity and sex with laying order explains male bias in extra-pair offspring in a wild bird population

Biology Letters ◽

10.1098/rsbl.2013.0616 ◽

2013 ◽

Vol 9 (5) ◽

pp. 20130616 ◽

Cited By ~ 4

Author(s):

Oscar Vedder ◽

Michael J. L. Magrath ◽

Marco van der Velde ◽

Jan Komdeur

Keyword(s):

Sex Ratio ◽

Wild Population ◽

Cyanistes Caeruleus ◽

Offspring Sex Ratio ◽

Bird Population ◽

Male Bias ◽

Laying Order ◽

Offspring Sex ◽

The Relationship ◽

Blue Tits

It has been hypothesized that parents increase their fitness by biasing the sex ratio of extra-pair offspring (EPO) towards males. Here, we report a male bias among EPO in a wild population of blue tits ( Cyanistes caeruleus ). This resulted from a decline in both the proportion of males and EPO over the laying order of eggs in the clutch. However, previous studies suggest that, unlike the decline in EPO with laying order, the relationship between offspring sex ratio and laying order is not consistent between years and populations in this species. Hence, we caution against treating the decline in proportion of males with laying order, and the resulting male bias among EPO, as support for the above hypothesis. Variable patterns of offspring sex and paternity over the laying order may explain inconsistent associations between offspring sex and paternity, between and within species.

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2nd to 4th Digit Ratio and Offspring Sex Ratio

Journal of Theoretical Biology ◽

10.1006/jtbi.2002.3014 ◽

2002 ◽

Vol 217 (1) ◽

pp. 93-95 ◽

Cited By ~ 37

Author(s):

J.T. MANNING ◽

S. MARTIN ◽

R.L. TRIVERS ◽

M. SOLER

Keyword(s):

Sex Ratio ◽

Digit Ratio ◽

Offspring Sex Ratio ◽

Offspring Sex

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The second to fourth digit ratio, sociosexuality, and offspring sex ratio

Behavioral and Brain Sciences ◽

10.1017/s0140525x05300057 ◽

2005 ◽

Vol 28 (2) ◽

pp. 283-284 ◽

Cited By ~ 1

Author(s):

Bernhard Fink ◽

John T. Manning ◽

Nick Neave

Keyword(s):

Sex Ratio ◽

Index Finger ◽

Ring Finger ◽

Relative Length ◽

Digit Ratio ◽

Sexually Dimorphic ◽

Offspring Sex Ratio ◽

Fourth Digit ◽

Offspring Sex ◽

Different Populations

Previous research has suggested that offspring sex ratio may be influenced by the actions of prenatal sex steroids, principally androgens. The relative length of the second (index finger) to the fourth digit (ring finger) has been reported to be a proxy to prenatal testosterone levels. This trait is sexually dimorphic, such that males display a significantly lower 2D:4D ratio (indicating higher testosterone exposure), and this dimorphism appears robust across different populations. We suggest that digit ratio (2D:4D) may form a useful marker to help explain variation in sex ratio and sociosexuality.

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