A new study suggests rising temperatures may be linked to a decline in the number of boys born. Researchers at the University of Oxford analyzed data from more than five million births across 33 countries in sub-Saharan Africa and India and found that when temperatures rise above 20°C (68°F), the ratio of male births decreases.
The study, published on March 9 in the Proceedings of the National Academy of Sciences (PNAS), found that heat exposure during early pregnancy may increase prenatal mortality, particularly among male fetuses. Researchers say this suggests that environmental factors such as climate change can influence human reproduction and population dynamics.
Scientists note that extreme heat can affect maternal health by disrupting the body’s ability to regulate temperature, potentially reducing oxygen and nutrients reaching the fetus. As global temperatures continue to rise, researchers say understanding these effects will be increasingly important.
Click through the gallery to learn more about the role of the Y chromosome and what its future could mean for human reproduction.