If new research proves to be correct, climate change will do away with the old adage that “its a man’s world.” According to research from Japan climate change may be killing male fetuses. The data shows that climate change may be behind a decline in the ratio of males to females in Japan. The study indicates that while the same number of males and females are being conceived fewer boy fetuses are being born. The researcher suggests that this may be due to increased vulnerability of male fetuses to warming and extreme weather.
The study shows that since the 1970s, temperature fluctuations have increased the number of deaths of male fetuses in Japan. During this period the number of males being born has been decreasing relative to female births.
The research found a correlation between weather extremes in Japan between 1968 to 2012 and the number of fetal deaths recorded in that country. They specifically examined the extreme heat in the summer of 2010 and found the there was an increase in the number of fetal deaths in September of that year, and nine months later, there was a decrease in the ratio of male to female babies born in the country.
A similar effect was evinced during the cold winter in 2011 (an increase in fetal deaths, followed by a decrease in the number of male babies born nine months later).
These findings suggest that “the recent temperature fluctuations in Japan seem to be linked to a lower male: female sex ratio of newborn infants, partly via increased male fetal deaths,” the researchers wrote in the Sept. 14, 2014 issue of the journal Fertility and Sterility.
Other researchers have hypothesized that male fetuses may be more vulnerable to stress factors like earthquakes and toxins. However, the earthquake and tsunami in Japan do not appear to be correlated with declining ratios of male to female births in this study.
This research corroborates a 2012 study which showed that between 1959-1961, a period of famine in China, more females were born than males.
It may well be that as the planet warms and climate change increases there will be fewer and fewer boys born.