Who came up with this hypothesis?

Some late breaking medical news. It seems that the ratio of lengths of the second finger and fourth finger (presumably what docs refer to as digits three and five) correlate to aggressive tendencies.

The researcher postulates that this ratio is a marker for intrauterine testosterone exposure. It is this intrauterine testosterone exposure that is believed to be the mechanism of this association.

Imagine how relieved I was to read the following qualification to the research: "behavior is influenced by many other factors Bailey said. Finger ratios are "just one piece of the puzzle," she said."

Indeed.