Ever since the ratio between your pointer and ring fingers was linked to homosexuality in men, it's been a constant source of amusement and scientific research. The 2D:4D ratio as it's officially known is linked to sex hormones and prenatal development, and at various times has been linked to sperm counts, aggression, musical ability, sexual orientation, sports prowess, autism, depression, heart attack, breast cancer, attractiveness, and much, much more.
While some of the correlations have been debunked, there are still plenty that definitely seem to be linked. So what exactly is going on in the womb to cause these two fingers to offer so much information about you? New research in the Proceedings of the National Academy of Sciences attempts to pick apart the causes of the ratio.
It's been thought for some time that the root cause is sex hormones during fetal development, but this research provides the first experimental evidence. The study traces the occurrence back an androgen and estrogen receptor that controls the growth of our fourth finger. During a very narrow window of digit development, the higher the amount of exposure to androgen, the longer the fourth finger. That's why males tend to have their 4D longer than their 2D, and females have them closer to the same length.
It's official, you can blame your mother's womb for why you're no good at skiing.