Students' fingertips may hold a clue to their academic test scores, a British researcher suggests.

Mark Brosnan, PhD, of the psychology department at England's University of Bath, studied 75 children aged 6-7 at a British elementary school.

One by one, the children had their hands photocopied at school. Brosnan then measured the length of the children's fingers, down to 0.01 millimeters (about 0.0004 inches).

Brosnan also checked the children's math and verbal scores on a standardized British academic exam. Then he compared the test scores and finger length data, especially the ratio of the length between the children's index and ring fingers.

At first glance, Brosnan found no clear patterns between the kids' test scores and their finger length. But that changed when he separated data on boys and girls.

Among boys, a low ratio of index finger length to ring finger length was associated with higher math scores. But that ratio wasn't associated for better or worse with boys' verbal test scores.

The opposite was true for girls. Among girls, a low ratio of index finger length to ring finger length was linked to better verbal test scores, but not to any patterns in girls' math test scores.

What difference does finger length make to test scores? Brosnan argues that finger length is linked to prenatal exposure to the hormone testosterone.

However, his study doesn't prove that, since it doesn't include the children's current or prenatal testosterone levels.

The study will be published in the British Journal of Psychology, states a news release from the University of Bath.

This article was reviewed by Louise Chang, MD