Human sex ratio as it relates to caloric availability

Williams, Robert J.; Gloster, Susan P.

doi:10.1080/19485565.1992.9988823

Cited by 49 publications

(39 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The few studies of the relationship between nutritional deficiencies and sex-ratio biasing in humans have not found consistent evidence of an association (Williams & Gloster 1992;Andersson & Bergstrom 1998). This may be partly because they have used BMI as a measure of maternal condition.…”

Section: Discussionmentioning

confidence: 99%

Strong mothers bear more sons in rural Ethiopia

Gibson

Mace

2003

Proc. R. Soc. Lond. B

View full text Add to dashboard Cite

In humans, there is evidence that the physiological cost to the mother of bearing sons is greater than of bearing daughters. Parents should manipulate the sex of offspring born in response to resource availability to maximize their reproductive success. Here, we demonstrate that, within a rural foodstressed community in southern Ethiopia, there is a strong association between the sex of the most recent birth and maternal nutritional status, measured either by body mass index or mid-upper arm muscle area (AMA) (measures of fat and muscle mass). The effect of muscle mass is very marked: those women in the upper 25th percentile of AMA were more than twice as likely to have had a recent male birth than those in the lowest 25th percentile.

show abstract

Section: Discussionmentioning

confidence: 99%

Strong mothers bear more sons in rural Ethiopia

Gibson

Mace

2003

Proc. R. Soc. Lond. B

View full text Add to dashboard Cite

show abstract

“…There is some evidence that wellnourished mothers may be more prone to deliver sons than daughters ( Williams & Gloster 1992 (table 1). Cagnacci et al 2004).…”

Section: Discussionmentioning

confidence: 99%

Temperature-related birth sex ratio bias in historical Sami: warm years bring more sons

2007

View full text Add to dashboard Cite

The birth sex ratio of vertebrates with chromosomal sex determination has been shown to respond to environmental variability, such as temperature. However, in humans the few previous studies on environmental temperature and birth sex ratios have produced mixed results. We examined whether reconstructed annual mean temperatures were associated with annual offspring sex ratio at birth in the eighteenth to nineteenth century Sami from northern Finland. We found that warm years correlated with a malebiased sex ratio, whereas a warm previous year skewed sex ratio towards females. The net effect of one degree Celsius increase in mean temperature during these 2 years corresponded to approximately 1% more sons born annually. Although the physiological and ecological mechanisms mediating these effects and their evolutionary consequences on parental fitness remain unknown, our results show that environmental temperature may affect human birth sex ratio.

show abstract

“…Therefore, the possibility that the duration of these famines was too brief to produce a consistent effect on sex ratio at birth cannot be ruled out [15]. Second, as both famines were regional in scale, they impacted relatively small populations, making it difficult to obtain study samples with large enough sample sizes to produce reliable effect estimates.…”

Section: Introductionmentioning

confidence: 99%

“…One observational study using human subjects compared the sex ratio of offspring between women with a good diet and women with a poor diet [10], whereas other observational studies compared the sex ratio of offspring between women with normal weight or body mass index (BMI) and those with low body weight or BMI [13,19,20]. Research has also estimated the relationship between nutritional condition and sex ratio at birth at the national level [15]. These observational studies lead to inconsistent findings regarding whether poor maternal nutritional conditions reduce the proportion of male births among human.…”

Section: Introductionmentioning

confidence: 99%

“…The empirical tests of the abovementioned adaptive sex ratio adjustment hypotheses have primarily focused on the effect of maternal nutritional condition [8][9][10][11][12][13][14][15][16][17][18]. Because social status and health condition are determined by a large number of genetic and environmental factors, they are difficult to experimentally manipulate for causal analysis.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Does famine influence sex ratio at birth? Evidence from the 1959–1961 Great Leap Forward Famine in China

Song

2012

Proc. R. Soc. B.

View full text Add to dashboard Cite

The current study examined the long-term trend in sex ratio at birth between 1929 and 1982 using retrospective birth histories of 310 101 Chinese women collected in a large, nationally representative sample survey in 1982. The study identified an abrupt decline in sex ratio at birth between April 1960, over a year after the Great Leap Forward Famine began, and October 1963, approximately 2 years after the famine ended, followed by a compensatory rise between October 1963 and July 1965. These findings support the adaptive sex ratio adjustment hypothesis that mothers in good condition are more likely to give birth to sons, whereas mothers in poor condition are more likely to give birth to daughters. In addition, these findings help explain the lack of consistent evidence reported by earlier studies based on the 1944–1945 Dutch Hunger Winter or the 1942 Leningrad Siege.

show abstract

Human sex ratio as it relates to caloric availability

Cited by 49 publications

References 24 publications

Strong mothers bear more sons in rural Ethiopia

Strong mothers bear more sons in rural Ethiopia

Temperature-related birth sex ratio bias in historical Sami: warm years bring more sons

Does famine influence sex ratio at birth? Evidence from the 1959–1961 Great Leap Forward Famine in China

Contact Info

Product

Resources

About