Sex Ratio at Birth and Mortality Rates Are Negatively Related in Humans
2011

Sex Ratio Variation in Humans

Sample size: 167 publication Evidence: high

Author Information

Author(s): Dama Madhukar Shivajirao

Primary Institution: Rural Veterinary Dispensary, Rajola, Bidar, India

Hypothesis

The study examines whether global sex ratio at birth variation can be explained by cross-national differences in mortality rates.

Conclusion

The study found that higher life expectancy and healthy life expectancy are associated with a higher sex ratio at birth, while various mortality rates negatively predict it.

Supporting Evidence

  • Life expectancy and healthy life expectancy were positively correlated with sex ratio at birth.
  • Mortality rates were significant negative predictors of sex ratios.
  • Countries with better health conditions tend to have more male births.

Takeaway

This study looks at how the number of boys and girls born in different countries can be affected by how long people expect to live and how many people die.

Methodology

The study used multiple regression modeling to analyze the relationship between sex ratio at birth and various mortality rates while controlling for fertility, wealth, and latitude.

Potential Biases

Potential biases may arise from the use of disparate factors as measures of parental investment ability.

Limitations

The study does not distinguish sex-specific embryonic mortality or other proximate mechanisms that may underlie the relationship between mortality rates and sex ratios.

Participant Demographics

The study analyzed data from various countries, excluding those with known son-preference practices.

Statistical Information

P-Value

p<0.001

Statistical Significance

p<0.001

Digital Object Identifier (DOI)

10.1371/journal.pone.0023792

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