Skip to main content
Article thumbnail
Location of Repository

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

By Ruth Mace and Rebecca Sear


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

Topics: HQ The family. Marriage. Woman, HN Social history and conditions. Social problems. Social reform, QH301 Biology, GN Anthropology
Year: 1997
DOI identifier: 10.1017/S0021932097004999
OAI identifier:
Provided by: LSE Research Online
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • (external link)
  • (external link)
  • (external link)
  • Suggested articles


    1. (1993). 506Rahman,M .&D a V anzo,
    2. (1996). Biased parental investment and reproductive success in Gabbra pastoralists. doi
    3. (1993). Birth interval and family effects on postneonatal mortality in Brazil. doi
    4. (1995). Birth spacing and infant and early childhood mortality in a high fertility area of Bangladesh: age-dependent and interactive effects. doi
    5. (1986). Bushmen birth spacing: a test for optimal interbirth intervals. doi
    6. (1985). Demographic determinants of infant and early child mortality—a comparative analysis. doi
    7. (1993). Determinants of birth interval in Vietnam: a hazard model analysis. doi
    8. (1995). Determinants of infant mortality in Malawi: an analysis to control for death clustering within families. doi
    9. (1993). Gender preference and birth spacing in Matlab,
    10. (1985). How the number of sons influences contraceptive use in Menoufia Governorate, doi
    11. (1996). Maternal mortality in a Kenyan pastoralist population. doi
    12. (1993). Nomadic pastoralists adopt subsistence strategies that maximise long-term household survival. doi
    13. (1972). Parental investment and sexual selection. In: Sexual Selection and the Descent of doi
    14. (1995). Patterns of clustering of child mortality in a rural area of Senegal. doi
    15. (1991). Reproductive life in nineteenth century Sweden: an evolutionary perspective on demographic phenomena. doi
    16. (1994). Sex preference and fertility in Peninsular Malaysia. doi
    17. (1993). Sex preference and its demographic and health implications. doi
    18. (1994). Sex preference and third birth intervals in a traditional Indian society. doi
    19. (1993). Sex-biased lactational duration in a human population and its reproductive costs. doi
    20. (1995). Subsequent pregnancy affects morbidity of previous child. doi
    21. (1984). The effect of birth spacing on childhood mortality in Pakistan. doi
    22. (1996). The effect of fertility reduction on infant and child mortality: evidence from Matlab in rural Bangladesh. doi
    23. (1996). When to have another baby: a dynamic model of reproductive decision-making and evidence from Gabbra pastoralists. doi

    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.