Did you know that men have the ring finger longer than the index finger, while in the hands of women the opposite usually happens? According to a study by biologists from the University of Florida and the Howard Highes Medical Institute, in the United States,the ratio of the fingers of the hands of men and women depends on the balance of sex hormones during embryonic development, specifically of androgen and estrogen.
The finding provides a biological explanation for the dozens of previous studies that link the proportion of fingers with traits such asmale sperm count, aggressiveness, musical ability, or success in sports, as well as certain diseases (autism, depression, breast cancer …).
“Besides understandingone of the strangest physical differences between men and women, It is exciting to think that the fingers will be able to tell us what signals we have been exposed to in the womb “, stresses Martin Cohn, co-author of the study published in the journalProceedings of the National Academy of Sciences(PNAS). “There is increasing evidence that adult diseases have fetal origins; with the new data we can help explain some of them,” adds the researcher.
In a series of experiments with mouse embryos, Cohn and his colleagues found that by manipulating the levels of sex hormones,more androgen equaled a fourth finger longer. And they concluded that hormonal signals regulate how fastprecursor cells of the bone skeleton divide. In addition, curiously the bones of each finger have different sensitivity to androgens and estrogens.
Since Roman times, human beings have associated the fourth finger with rings. And in many cultures,the longer the ring finger in a man, the more fertile he is considered.
