Found 2135 Hypotheses across 214 Pages (0.045 seconds)
  1. The sex ratio should be higher in countries where contraception is widely practiced.Barber, Nigel - Sex Ratio at Birth, Polygyny, and Fertility: A Cross-National Study, 2004 - 2 Variables

    This article discusses the variation in sex ratios at birth among human populations and the possible explanations for this variation. One possible explanation is the timing of intercourse and its relationship to the frequency of intercourse, which can affect the timing of conception. The article presents evidence that the male/female sex ratios of 148 countries declined with total fertility rates and polygyny intensity and increased with contraception use in correlational analysis. These results were independent of mother's age and level of economic development. The predictive effect of polygyny and contraception disappeared when total fertility was added to the equation. The article also considers other possible explanations for the variation in sex ratios, such as genetics, hormones, nutrition, and social factors.

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  2. The sex ratio at birth will decline with polygyny.Barber, Nigel - Sex Ratio at Birth, Polygyny, and Fertility: A Cross-National Study, 2004 - 2 Variables

    This article discusses the variation in sex ratios at birth among human populations and the possible explanations for this variation. One possible explanation is the timing of intercourse and its relationship to the frequency of intercourse, which can affect the timing of conception. The article presents evidence that the male/female sex ratios of 148 countries declined with total fertility rates and polygyny intensity and increased with contraception use in correlational analysis. These results were independent of mother's age and level of economic development. The predictive effect of polygyny and contraception disappeared when total fertility was added to the equation. The article also considers other possible explanations for the variation in sex ratios, such as genetics, hormones, nutrition, and social factors.

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  3. "Teen pregnancy will increase as the sex ratio declines" (30).Barber, Nigel - On the relationship between country sex ratios and teen pregnancy rates, 2000 - 2 Variables

    This study attempted to replicate earlier findings regarding population structure and teen pregnancy rates. Findings support the previous predictions that sex ratio, economic development, and latitude are all inversely related to teen birth rates.

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  4. Teen pregnancy will decline as economic development increases (33).Barber, Nigel - On the relationship between country sex ratios and teen pregnancy rates, 2000 - 2 Variables

    This study attempted to replicate earlier findings regarding population structure and teen pregnancy rates. Findings support the previous predictions that sex ratio, economic development, and latitude are all inversely related to teen birth rates.

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  5. "Teen birth rates will be lower at high latitudes" (30).Barber, Nigel - On the relationship between country sex ratios and teen pregnancy rates, 2000 - 2 Variables

    This study attempted to replicate earlier findings regarding population structure and teen pregnancy rates. Findings support the previous predictions that sex ratio, economic development, and latitude are all inversely related to teen birth rates.

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  6. Sex ratio at birth will be negatively correlated with total fertility rate.Mace, Ruth - Testing evolutionary hypotheses about human biological adaptation using cros..., 2003 - 2 Variables

    Can physiological variation in human populations be attributed to environmental variables? Arguing for the importance of phylogenetic comparative methods, the authors present the results of previous research by Holden & Mace (1997) on lactose intolerance as well as introduce new research on sex ratio at birth. The authors suggest that global variance in sex ratio at birth is an adapted response to the physiological costs of giving birth to boys in high fertility populations.

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  7. Sex ratio at birth will be positively correlated with sex ratio of children between 0 and 14 years old.Mace, Ruth - Testing evolutionary hypotheses about human biological adaptation using cros..., 2003 - 2 Variables

    Can physiological variation in human populations be attributed to environmental variables? Arguing for the importance of phylogenetic comparative methods, the authors present the results of previous research by Holden & Mace (1997) on lactose intolerance as well as introduce new research on sex ratio at birth. The authors suggest that global variance in sex ratio at birth is an adapted response to the physiological costs of giving birth to boys in high fertility populations.

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  8. Sex ratio at birth will be positively correlated with sex ratio in adults between 15 and 65 years old.Mace, Ruth - Testing evolutionary hypotheses about human biological adaptation using cros..., 2003 - 2 Variables

    Can physiological variation in human populations be attributed to environmental variables? Arguing for the importance of phylogenetic comparative methods, the authors present the results of previous research by Holden & Mace (1997) on lactose intolerance as well as introduce new research on sex ratio at birth. The authors suggest that global variance in sex ratio at birth is an adapted response to the physiological costs of giving birth to boys in high fertility populations.

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  9. Sex ratio at birth will be negatively correlated with maternal mortality ratio.Mace, Ruth - Testing evolutionary hypotheses about human biological adaptation using cros..., 2003 - 2 Variables

    Can physiological variation in human populations be attributed to environmental variables? Arguing for the importance of phylogenetic comparative methods, the authors present the results of previous research by Holden & Mace (1997) on lactose intolerance as well as introduce new research on sex ratio at birth. The authors suggest that global variance in sex ratio at birth is an adapted response to the physiological costs of giving birth to boys in high fertility populations.

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  10. Sex ratio at birth will be negatively correlated with the mortality rate of those under 1 year of age.Mace, Ruth - Testing evolutionary hypotheses about human biological adaptation using cros..., 2003 - 2 Variables

    Can physiological variation in human populations be attributed to environmental variables? Arguing for the importance of phylogenetic comparative methods, the authors present the results of previous research by Holden & Mace (1997) on lactose intolerance as well as introduce new research on sex ratio at birth. The authors suggest that global variance in sex ratio at birth is an adapted response to the physiological costs of giving birth to boys in high fertility populations.

    Related HypothesesCite