More boys are born than girls. For every 100 girls born, 105 boys occur. An odd quirk of nature that occurs throughout the world. Except, that is, when it comes to women of sub-Saharan African descent.
Right from birth, men across the spectrum suffer a high attrition rate — leading to the tendency of more females surviving than males. By age 65 and over, the trend is set — there are substantially more females than males in most countries. Women survive. Men don’t.
It seems, from a point-of-view, that from birth the boy is fighting a losing battle. The boy is three to four times more likely than the girl to have developmental disorders like autism and dyslexia. The girl will learn language earlier and develop richer vocabularies. The list of handicaps do not end there. The girl will demonstrate insight and judgment earlier in adolescence, not to mention the girl hears better. Teenage boys are more likely to commit suicide than girls and are more likely to die violent deaths before adulthood.
You would think that after all of this the tendency for more boys to be born would be a futile attempt by mother nature.
To some this is merely a question of numbers and statistics, but to others the numbers hold questions about societies, lives, and the unapparent deep-seated socio-economic differences between us. In every country the end statistic is the same. More males. Except women in sub-Saharan Africa give birth to more females than non-Black women in all other parts of the world. A curious fact that seems to fore-go national or continental boundaries, as similar trends have also been observed in the United States among the African-American population.
In general, across a population, trends in sex ratio cannot be attributed to any single set of risk factors. And dozens of factors, too numerous to list, can be attributed to the central question of why more males are born and why there seems to be a decline. Even events occurring after conception may perhaps skew the outcome of a male.
So, is it really a case of Black Women giving birth to more females? Or does it just seem that way? The fact that fertility is generally and substantially higher in sub-Saharan African women as well as African-American women could just simply point to the fact that the more you give birth the less likely it is that it will be a boy.
Perhaps it takes more calories to create a boy than it does a girl. Lower caloric intake might cause an unequal sex ratio at birth as foetal sex and maternal diet are linked. The exact nature of that link is as of yet unidentified.
A study of 740 British women showed that a majority of those who had the highest energy intake gave birth to boys. A statistic like this can easily be extrapolated and compared to those mothers in less developed nations that consume fewer calories, but easily breaks down when you displace it to Black Women in the US.
In the end the answer, it seems, is yet to reveal itself. But one thing is certain — we are approaching parity. A 1 to 1 sex ratio seems to be the overwhelming trend that we are heading to. The shrinking sex ratio. Black Women represent the first racial group where this trend can be seen evidently. For what reason and as a result of what stimulus still remains to be seen.
Davis, D., Webster, P., Stainthorpe, H., Chilton, J., Jones, L., & Doi, R. (2007). Declines in Sex Ratio at Birth and Fetal Deaths in Japan, and in U.S. Whites but Not African Americans Environmental Health Perspectives, 115 (6), 941-946 DOI: 10.1289/ehp.9540
Amadu Jacky Kaba (2008). Sex Ratio at Birth and Racial Differences: Why Do Black Women Give Birth to More Females Than NonBlack Women? African Journal of Reproductive Health, 12