issues and experts

Boy or girl? New study answers fundamental evolutionary biology question

September 30, 2020


Mikael Mokkonen, lecturer, Biological Sciences


  • tracking of enclosed field populations
  • mathematical modelling
  • quantitative genetic modelling
  • laboratory husbandry/artificial selection

Shradhha Sharma; University Communications and Marketing, 604.202.2504,


A study investigating the genetics of a pregnancy disorder has found the same gene also plays a role in whether a woman would give birth to a girl or a boy.

A recent research paper in EBioMedicine, which is published by The Lancet medical journal, and co-authored by SFU biological sciences professor Mikael Mokkonen shares interesting empirical evidence to explain a fundamental paradox of evolutionary biology—the 50-50 population sex ratio.

The findings were arrived at during a study focussed on the condition of preeclampsia—a hypertensive pregnancy disorder that affects millions of women globally, especially in countries where blood-borne diseases, such as malaria are common.

Researchers identified a particular gene associated with a higher incidence of preeclampsia, and their findings suggest that the same gene also has a statistical association with having a son or a daughter.

“It is the result of an interesting evolutionary tug-of-war over the mother’s immune system during pregnancy,” says Mokkonen. 

The study also suggests a potential treatment for preeclampsia with the drug hydroxychloroquine, which is used to treat malaria, and coincidentally has been repeatedly recommended by U.S. President Donald Trump as an effective cure for COVID-19 without any scientific basis.

Mokkonen is available to talk more about the research and its wider implications for reproductive health and health policy.


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