A new study from the University of Oxford in the UK has found that climate change may even affect whether more boys or girls are born. Scientists discovered that the proportion of female babies born rises significantly in high-temperature environments, suggesting that global warming not only changes the weather but might even reshape the gender structure of the future population.
According to the Daily Mail, the Oxford research team analyzed birth data from over 5 million cases in 33 countries, including sub-Saharan Africa and India, and found that increasing temperatures affect the sex ratio at birth. The results reveal that whenever the average temperature exceeds 20 degrees Celsius, the proportion of female babies born goes up, while the proportion of male babies goes down.
Study author Abdel Ghany pointed out that extreme climate not only poses public health threats but also impacts fetal survival, thereby altering population composition and the gender balance. Generally speaking, the global sex ratio at birth is not 1:1; it is roughly 101 to 102 males for every 100 females. However, the study found that high temperatures reduce the number of male births through various mechanisms. In Africa, this appears related to heat stress in pregnant women making it harder for male fetuses to survive; in India, the effect is more pronounced during mid-pregnancy, particularly in older mothers, women with multiple pregnancies, or families that have not yet had a son.
The researchers believe that male fetuses may be more sensitive to environmental stress, which makes them more likely to be miscarried in high temperatures, leading to a gender ratio shift favoring females.
Another study by the University of Manchester in the UK also found that the season influences male fertility. Researchers analyzed semen samples from over 15,000 men in Denmark and Florida, USA, and found that, regardless of climate differences, sperm quality is best in summer and worst in winter.
Experts warn that global warming may subtly change human reproduction patterns—in the future, not only might birth numbers differ but even the male-to-female ratio could be reshuffled by the 'weather.'
Study author Abdel Ghany pointed out that extreme climate not only poses public health threats but also impacts fetal survival, thereby altering population composition and the gender balance. Generally speaking, the global sex ratio at birth is not 1:1; it is roughly 101 to 102 males for every 100 females. However, the study found that high temperatures reduce the number of male births through various mechanisms. In Africa, this appears related to heat stress in pregnant women making it harder for male fetuses to survive; in India, the effect is more pronounced during mid-pregnancy, particularly in older mothers, women with multiple pregnancies, or families that have not yet had a son.
The researchers believe that male fetuses may be more sensitive to environmental stress, which makes them more likely to be miscarried in high temperatures, leading to a gender ratio shift favoring females.
Another study by the University of Manchester in the UK also found that the season influences male fertility. Researchers analyzed semen samples from over 15,000 men in Denmark and Florida, USA, and found that, regardless of climate differences, sperm quality is best in summer and worst in winter.
Experts warn that global warming may subtly change human reproduction patterns—in the future, not only might birth numbers differ but even the male-to-female ratio could be reshuffled by the 'weather.'