The key here is digit ratio, or the difference in length between the index and ring fingers. In women, the index finger is typically the same length or longer than the ring finger (high digit ratio); in men, the opposite is true (low digit ratio). Digit ratio is one of the few sex differences present at birth, and is directly influenced by exposure to prenatal sex hormones. In other words: The bigger the difference in finger lengths, the more testosterone exposure in the womb.
Keeping in mind that correlation is not necessarily causation, there’s still a slew of fascinating connections between digit ratio and everything from musical ability (masculine hands do better) to breast cancer (people with feminine hands are at higher risk). As someone with a low digit ratio, I’m supposedly better at engineering, military-related occupations and chess. I am also more likely to end up in prison, go mad and die young. In contrast, people with long index fingers are more likely to have eczema and hay fever, which isn’t quite comparable to the horrors that may be in store for me.
It gets interesting when it comes to those of us with digit ratios usually associated with the opposite sex. If I were a man, I would have a larger-than-average penis — but since I’m not, there are seemingly few benefits to reap. For both genders, we’re more likely to be gay. Women like me are less likely to be fertile and more likely to have autism. On the other hand (no pun intended), I should enjoy greater professional success, which could explain why my name has been at the top of the Guardian staff box for going on two years, and probably won’t get breast cancer. Similarly, men with feminine hands have a lower risk for prostate cancer.
Though the correlations are interesting, digit ratio ultimately means little when environmental factors aren’t taken into account. The results are more indicators than predictors, and even now — without knowing whether I’ll develop cancer or end up in prison — there’s glaring errors in the connection between my hands and my abilities. According to the British Journal of Psychology, people like me usually have a huge difference in literacy and math skills (check), favoring math (dead wrong). Considering I’m neither gay nor especially athletic, had a perfect writing SAT and couldn’t break 700 in math, there may be hope for me yet.