And it wasn't just their ring fingers that were bigger: What makes the brain typically male or female is the hormones in the mother's womb that help embryos to develop. Have the person in question fold a small piece of paper into a little tent. Using the proximal phalange of the index finger as a point of reference, the tip of the human thumb typically ends near the middle of this phalange - see: In case the tip of the thumb ends near this imaginary line one can conclude that the length of the thumb is: Testosterone lengthens the fetal fingers, while estrogen stops their growth, and thus the balance of the two hormones can affect the ring finger and index finger differently.
More men might be wired this way than women, but if you are wired this way, it transcends gender.
How to tell the difference between a man and a woman…
My ring finger is almost an inch longer than my index finger on both hands and I am definitely a woman. But in the Italian study, the female entrepreneurs actually had more of a male pattern: In my dissertation study I have studied this aspect of the hand in 30 males and 75 females. He believes digit ratio is an important, if indirect, tool for studying the fetal brain and the womb, an environment that's off-limits to scientists except for analysis by amniocentesis. In the section function of the hand is the human thumb described to be relatively long compared to ape thumbs, because in humans the thumb is typically longer than the 5th digit pinky while in apes the thumb is always shorter than the 5th digit: Next to body hair, fat percentage and finger ratios there is actually another rather significant phenomenon which is also found more often in males than in females: All the ways the brain is affected aren't yet known.