Climate change may be causing 'subtle changes in sex ratios', according to a new study
Global warming could potentially be affecting human biology, according to a study undertaken in Japan.
Warmer temperatures could lead to fewer male babies born according to research conducted by Dr Misao Fukuda, lead study author and founder of the M&K Health Institute in Hyogo.
The scientists analysed the yearly mean temperature differences between 1968 and 2012 in Japan in a bid to answer the question if rising temperatures, which have increased an average of 0.69 degrees Celcius per 100 years during the past century, is having any impact on the sex ratio of newborn infants.
Stress stemming directly from "climate events caused by global warming" might be affecting the sex ratio, Fukuda told CNN. Though scientists do not know how stress affects gestation, Fukuda theorizes that the vulnerability of Y-bearing sperm cells, male embryos and/or male fetuses to stress is why "subtle significant changes in sex ratios" occur.
This study was echoed by research in Scandinavian countries where Samuli Helle, a senior researcher in the Section of Ecology, Department of Biology at the University of Turku in Finland, also found that "warmer temperatures bring sons."
Dr Fukuda believes that any potential effects of climate change on the newborn sex ratio "may not be uniform" around the world. "It may depend on different environmental factors of each place," he told the American news outlet. "Extremely hot or cold weather" caused more of an impact on the sex ratio than moderate changes.
While the findings are still tentative, there is one thing that Dr Fukuda is certain of:
"Climate change is going to change the characteristics of the population in ways that maybe can't be anticipated."