The length of a man’s fourth finger is linked to his libido, according to new research. Scientists have discovered that its size is actually determined by the levels of male and female sex hormones during embryonic development. The more testosterone a baby is exposed to, the longer its ring finger is likely to be, the team’s observations show, and high levels of testosterone tend to indicate higher sex drive, the researchers said. The length of the fourth finger is related to sperm count, aggressive behavior, sexual orientation. This finger is full of receptors for sex hormones, says Professor Martin Kohn, a biologist at the University of Florida. NEWS_MORE_BOX A previous study showed that according to the ratio of the lengths of the index and ring fingers, the size of the penis can be determined. The Korean scientists measured the length of the index and ring fingers, then the length of the penis, but not in an erect state. It is believed that the ratio of the fingers of the left hand is more indicative. According to the results, men with a shorter index finger than the ring finger enjoyed a larger organ, compared to those whose fingers were equal or opposite in length.