Take a look at your hand. Is your ring finger shorter than your index finger? Little did you know, but this finger can tell more than just if you’re married or not.

Ring fingers of men are generally longer than their index fingers. The opposite is the case for women, where the index finger is longer than ring. National Geographic reports on a study released by the Howard Hughes Medical Institute in Florida:

Differences in finger length have been repeatedly linked to a range of human traits, from aggression to musical ability to sexual orientation. There are also connections to health problems such as autism, depression, heart attacks, and cancer.

“It’s difficult to look at an adult or a newborn child and determine what was happening during their embryonic development,” said study leader Zhengui Zheng.

“But the discovery that digit proportions reflect the prenatal hormonal environment helps us to explain all those correlational studies,” said Zheng, who works in the laboratory of study co-author Martin Cohn.

The difference in size for the ring finger and index finger, scientists studying mice have found, is due to estrogen and testosterone levels during prenatal development. To prove this, the researchers blocked the receptors in the embryonic mouse’s limb buds that would receive the hormone, then they played with hormone levels in momma mouse. Here’s what they found:

Male mice that lacked testosterone receptors in the womb were born with shorter, typically feminine digit proportions, or had index digits longer than their ring digits. Male mice without estrogen receptors had longer ring digits.

Female mice that lacked an estrogen receptor were born with longer digits, and those that did not have testosterone had shorter, superfeminine digits.

. . .

In the ring digit, testosterone stimulates cell division, building up cartilage and bone to make the digit longer. Estrogen, on the other hand, slows down cell division, leading to a shorter digit.

The results of this study mean that the ring finger could be used by doctors as a tool for figuring out causes of disease, malformities and some behavioral traits. It gives an accurate representation of some of the hormones the person was exposed to in the womb.

If you’re a man, and your index finger is longer than your ring finger. It’s not a bad thing. You could have just gotten an extra dose of estrogen during development.