Men with long index fingers may be less likely to develop prostate cancer than those with shorter ones, a study has found.
Scientists at the University of Warwick and the Institute of Cancer Research (ICR) discovered that the ratio of index finger length to ring finger length may give an important indication of a man's risk of prostate cancer.
Their study, which is published in the British Journal of Cancer, found that men whose index finger was longer than their ring finger were one-third less likely to develop the disease than those with longer ring fingers.
The research involved more than 1,500 prostate cancer patients and more than 3,000 healthy volunteers, all of whom were questioned between 1994 and 2009.
The link is thought to be explained by levels of sex hormones that babies are exposed to in the womb.
Lower levels of testosterone are associated with longer index fingers, and researchers now believe that less exposure to testosterone before birth may help to protect men against prostate cancer in later life.
Joint senior author Professor Ros Eeles, from the ICR and the Royal Marsden NHS Foundation Trust, concluded: 'Our results show that relative finger length could be used as a simple test for prostate cancer risk, particularly in men aged under 60.
'This exciting finding means that finger pattern could potentially be used to select at-risk men for ongoing screening, perhaps in combination with other factors such as family history or genetic testing.'
However, Dr Helen Rippon from the Prostate Cancer Charity urged men with shorter index fingers not to be 'unduly worried'.
She told the BBC: 'They share this trait with more than half of all men and it does not mean they will definitely develop prostate cancer in later life.'