Climate change could affect the ratio of human males to human females that are born in some countries, a new study from Japan suggests. The researchers found that male fetuses may be particularly vulnerable to the effects of climate change.
Since the 1970s, temperature fluctuations from the norm have become more common in Japan, and at the same time there has been an increase in the deaths of male fetuses, relative to the number of deaths of female fetuses in that country, according to the study.
Over this period, the ratio of male to female babies born in the country has been decreasing, meaning there have been fewer and fewer male babies born relative to the number of female babies born.
This suggests that climate warming or climate extremes could negatively affect male fetuses, study researcher Dr. Misao Fukuda, of M&K Health Institute in Ako, Japan, told Live Science in an email.