Is Climate Change Affecting Gender Ratios?

The controversial topic of global warming has already exhibited significant effects on our communities, our health, our climate, and now our gender.

Lexie Ehlers
For The Record

A hotly debated new study suggests that global warming may be directly impacting our human biology. Specifically, climate change could alter the proportion of male and female newborns. A recent study in Japan found a link between fluctuations in temperature and a lower male-to-female sex ratio at birth. This suggests that the conception of boys is especially vulnerable to external stress factors, wrote Dr. Misao Fukuda, the lead study author and founder of the M&K Health Institute in Hyogo, Japan.
The scientific data claims more males appear to be born in places where temperatures rise. The study goes on to claim fewer boys are born in places with extreme environmental changes and disasters, such as drought or wildfire caused by global warming.
Fukuda and his colleagues published a separate study last summer. The study focused on births in areas hit by environmental events that caused extreme stress. They included the Kobe earthquake of 1995, the Great East Japan Earthquake of 2011 and subsequent nuclear disaster at the Fukushima power plant, and the 2016 earthquakes. Nine months after these disasters, the proportion of male babies born in these areas declined between six percent and fourteen percent from the previous year. This data proposes that significant stress affects gestation, which in turn alters the newborn sex ratio.
Scientists are not sure about how exactly stress affects gestation. However, Fukuda theorizes that the vulnerability to stress on mothers is why “subtle significant changes in sex ratios” occur. Scientists believe that the sex ratio is equal at conception, explained Steven Orzack, president and senior research scientist of the Fresh Pond Research Institute in Cambridge, Massachusetts. However, more than half of all human conceptions die during gestation, and this results in a sex imbalance at birth. Orzack stated, “Overall, more females die during pregnancy than do males. So that’s why there’s an excess number of males at birth.”
Ultimately, for Fukuda, the importance of the newborn sex ratio is less societal and more medical. The importance of the newborn sex ratio is as a “sensitive reproductive health indicator,” he stated. Ray Catalano, a professor in the school of public health at the University of California, stated his concern of evolution: “Humans are incredibly adaptable, we got through the Ice Age.” He has no fears that we will adapt to the current climate change. Catalano further stated, “What will we be after that adaptation? Will we be different? Climate change is going to change the characteristics of the population in ways that maybe can’t be anticipated.” Global warming has had a variety of effects on our planet, which now includes the determination of gender. What other effects will arise from global warming in the future?




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