Finger Length & Testosterone

You may have had your palm read at some carnival or Renaissance Faireat one point, forking over $20 to a faux Gypsy as she gushed over the length of your “life lines.” The science may have been dubious, but it was all in good fun (and even faux gypsies have to eat, right?). But a neuroscientist in Norway believes he can tell a lot from your hand – specifically from the lengths of your fingers.

Carl Pintzka, a medical doctor and researcher at the Norwegian Competence Service for Functional MRI, saysthat the size relationship between your index finger and ring finger shows how much testosterone you have been exposed to in the womb. This, in turn, is an indicator as to how well you can perform certain physical tasks – as well as your propensity for having ADHD and Tourette's Syndrome.

As fetuses, we – all of us, men and women – are exposed to testosterone. If your index finger is relatively short compared to your ring finger, know that you have been exposed to a lot of testosterone in utero. If you've a relatively long index finger, it's an indicator that your exposure to testosterone in the womb was lower.

“One mechanism behind this relationship is the difference in the receptor density for estrogen and testosterone in the various fingers in utero. This relationship has also been shown to remain relatively stable after birth, which implies that it’s strictly the fetal hormone balance that determines this ratio,” says Pintzka.

Low levels of testosterone are associated with better abilities in verbal memory tasks, such as remembering lists of words, but also an increased propensity for anxiety and depression – diseases that are more common in women.

And what if you're scoring high on the fetal testosterone exam...?

“The greatest effect has been found for various physical and athletic measures, where high levels of prenatal testosterone are consistently linked with better capabilities,” Pintzka says. “Beyond this we find a number of uncertain results, but a general feature is that high levels of testosterone generally correlate with superior abilities on tasks that men usually perform better, such as various spatial tasks like directional sense,” he adds.

But it's not all protein shakes and high fives for the extreme fetaltestosterone crowd, however. High levels of testosterone in utero are associated with an increased risk of developing diseases that are more common in men, such as ADHD, Tourette’s syndrome and autism.

Pintza published his research in Science Direct.