The birth interval and the sex of children in a traditional African population: an evolutionary analysis

Mace, R.; Sear, R.

Abstract

Birth interval is a major determinant of rates of fertility, and is also a measure of parental investment in a child. In this paper the length of the birth interval in a traditional African population is analysed by sex of children. Birth intervals after the birth of a boy were significantly longer than after the birth of a girl, indicating higher parental investment in boys. However, in women of high parity, this differential disappeared. Birth intervals for women with no son were shorter than for those with at least one son. All these results are compatible with an evolutionary analysis of reproductive decision-making. First born sons have particularly high reproductive success, daughters have average reproductive success and late born sons have low reproductive success. The birth interval follows a similar trend, suggesting that longer birth intervals represent higher maternal investment in children of high reproductive potential.

Citation

Mace, R., & Sear, R. (1997). The birth interval and the sex of children in a traditional African population: an evolutionary analysis. Journal of Biosocial Science, 29(4), 499-507. https://doi.org/10.1017/s0021932097004999

• Journal Article Type: Article
• Publication Date: Oct 1, 1997
• Deposit Date: Oct 28, 2010
• Publicly Available Date: Feb 1, 2011
• Journal: Journal of Biosocial Science
• Print ISSN: 0021-9320
• Electronic ISSN: 1469-7599
• Publisher: Cambridge University Press
• Peer Reviewed: Peer Reviewed
• Volume: 29
• Issue: 4
• Pages: 499-507
• DOI: https://doi.org/10.1017/s0021932097004999
• Public URL: https://durham-repository.worktribe.com/output/1516092