Recent findings show that the length of your fingers may indicate your cognitive leanings. From the article:

Specifically, boys whose index fingers were short compared with their ring fingers tended to excel at numbers and girls with index and ring fingers of similar length tended to do better on the verbal portion of the test.

....

Researchers believe hormones explain the findings. Finger length is thought to be determined in the womb, with exposures to testosterone and estrogen playing a key role. Greater testosterone exposure appears to result in a shorter index finger relative to the ring finger, while estrogen encourages more equality between the two fingers.

Apparently, testosterone promotes development of spatial and mathematical skills, while estrogen affects language skills. Is that why women talk all the time and men pay all the bills?

Hmm, this testosterone-estrogen dynamic sure can explain a lot of the gender-specific behavior we have. Here's a few I've listed down for violent reactions or interactions, however you prefer it.

1. Guys always wanting to score. (Testosterone = math skills)

2. Women asking grammatically correct yet impossible-to-answer questions like, "Do I look fat in these jeans?" (Estrogen = language skills)

3. Gay guys jabbering anywhere and anytime. (Guess which hormone is dominant here?)