For some unknown reason, humans at tropical latitudes produce more females.
… data collected from 202 countries over a decade show that latitude is a primary factor influencing the ratio of males and females produced at birth; countries at tropical latitudes produced significantly fewer boys (51.1% males) annually than those at temperate and subarctic latitudes (51.3%).
This pattern remained strong despite enormous continental variation in lifestyle and socio-economic status, suggesting that latitudinal variables may act as overarching cues on which sex ratio variation in humans is based.
It’s barely noticeable, a 0.2% difference, yet consistently present with observation. As with so many things, we see the pattern, the anomaly, but the cause may remain hidden.
So many mysteries. It is easy to waste time on small stuff if you are a curious person.
What are the world’s top ten most important unanswered questions? Time to re-focus.