A new study shows that women who have a large bra size are more likely to develop diabetes than those with an A cup.
And the research, which is published in the Canadian Medical Association Journal, suggests that measuring a woman's breast size at the age of 20 may help predict whether she will go on to develop diabetes in middle age.
The scientists found that women with a C or D cup are more likely to develop type 2 diabetes than those with an A cup.
Type 2 is often linked to lifestyle factors, such as obesity and a lack of exercise, but even after these are accounted for, researchers found that the risk was still high.
And the study suggests that the risk of diabetes could be independent of how large somebody's body mass index (BMI) is.
Libby Dowling, care adviser at Diabetes UK, welcomed the report but said that it is far too early to use breast size as an indicator of a woman's risk of developing the disease.
She said: "We recommend that women continue to measure their waist.
"If their waistline is 31.5in or more and they have a family history of diabetes or are over 40 then they should see their doctor for a simple blood test to see if they have diabetes."