Finger length may be a simple way to tell if a woman has the potential to be a tennis star like Serena Williams or a top runner like Paula Radcliffe.
Finger lenght may reveal sporting prowess
A King's College London team found women whose ring finger is longer than their index finger are more likely to achieve higher levels in sport.
The ratio between the fingers has already been linked to traits in men like cognitive ability and sperm count.
The study appears online in the British Journal of Sports Medicine.
The researchers, from King's Twin Research Unit, examined hand X-ray images of 607 female twins aged 25-79 from the UK.
In each case they measured the lengths of the second and fourth fingers of each hand.
The volunteers also ranked their highest level of achievement in a list of 12 sports on a questionnaire.
The researchers found women with longer fourth fingers were significantly more likely to be among the top achievers in all the sports listed.
In particular, they were likely to excel at running, and sports such as football and tennis, which require running prowess.
Lead researcher Professor Tim Spector said: "The reasons for these findings are unclear.
"Previous studies have suggested the change in finger length was due to changes in testosterone levels in the womb but we also found that finger length was 70% heritable with little influence of the womb environment.
"This suggests that genes are the main factor and that finger length is a marker of your genes."
The ratio between the two fingers is fixed before birth and remains constant during life.
As this is the case, the researchers suggest that examining finger length may help to identify talented individuals at an early, pre-competitive stage.
No specific genes have yet been identified that control finger length.
Experts believe it is likely that multiple genes are responsible.
John Brewer, director of the Lucozade Sports Science Academy, said: "It has always been said that in order to succeed in high level sport you need to chose your parents carefully, because genetic characteristics do play a huge role.
"Identifying a single physiological indicator to show whether somebody has a predisposition for high level sport is, in effect, the holy grail of talent identification programmes."
However, Mr Brewer said it was unlikely that one physical indicator could predict ability across the whole range of sports, as the attributes required to succeed varied so widely.
He also stressed that UK sports authorities were as keen to encourage widespread participation, as to promote exceptional talent.