Children's academic strengths can be predicted by the relative lengths of their fingers, claim researchers.
The future is in their hands?
The study of 75 seven-year-old children found those with shorter ring fingers than their index fingers did better in tests at literacy than maths.
Those with longer ring fingers were better at maths than literacy, said the British Journal of Psychology study.
The UK team said the link was caused by children's exposure to different levels of hormones in the womb.
Head of the Department of Psychology at Bath University and research leader Dr Mark Brosnan said: "Testosterone has been argued to promote development of the areas of the brain which are often associated with spatial and mathematical skills.
"Oestrogen is thought to do the same in the areas of the brain which are often associated with verbal ability.
"Interestingly, these hormones are also thought have a say in the relative lengths of our index and ring fingers."
Children exposed to more testosterone tended to have longer ring fingers, while those exposed to more oestrogen had longer index fingers.
He added: "We can use measurements of these fingers as a way of gauging the relative exposure to these two hormones in the womb and as we have shown through this study, we can also use them to predict ability in the key areas of numeracy and literacy."
The research team compared the ratio between the two fingers with the seven-year-olds' school test results, and said they found a "valid relationship" between them.
Dr Brosnan said: "We're not suggesting that finger length measurements could replace SAT tests.
"Finger ratio provides us with an interesting insight into our innate abilities in key cognitive areas."