Doctors say they have found evidence to suggest that diabetes may run in the family.
The cause may lie inside the womb
A study in France suggests that people whose mothers have one type of diabetes may be at increased risk of developing the other type later in life.
The increased risk may have more to do with exposure to the disease in the womb rather than genetics.
Experts believe that while further research is needed the findings could lead to changes in the medical advice given to diabetic women who are planning to have children.
The French researchers found that people whose mothers have type one diabetes may be at increased risk of developing type two diabetes.
People with type one or insulin-dependent diabetes usually develop the condition when they are children or young adults. They are generally unable to produce any insulin at all.
Prevention of diabetes may need to be started as early as possible
Dr Andrew Greenberg, Tufts University
People with type two or non-insulin dependent diabetes usually develop the condition when they are over the age of 40 and are overweight. They do not make enough insulin, or are unable to make proper use of it.
Little is known about why people get either type. However, there are clear risk factors for type two diabetes, including physical inactivity and obesity.
But this latest study, published in the medical journal The Lancet, suggests that for some people the cause may lie elsewhere.
Professor Jean Francois Gautier and colleagues at the H˘pital Saint-Louis in Paris carried out tests on 31 people who were born after one of their parents had been diagnosed with type one diabetes.
The found that those with type one diabetic mothers were more likely to have problems making enough insulin - a possible sign of type two diabetes - compared with those who had fathers with the disease.
In the womb
The researchers were able to exclude other factors which might influence this result, such as genetics or body fat.
This led them to conclude that the differences could be linked to the fact that these people may have been exposed to the disease in the womb.
However, they were unable to explain why this may be the case and suggested that further research is needed in this area.
The findings were welcomed by experts.
In an accompanying editorial, Dr Andrew Greenberg of Tufts University in Boston, United States, suggested the findings could change the way doctors fight the disease.
"Although the number of study participants was small, the data are enticing," he said.
"Prevention of diabetes may need to be started as early as possible, starting with improving the metabolic status of the mother before conception and during pregnancy.
"Such measures could contribute to reducing the epidemic of diabetes and its complications in the years to come."
Eleanor Kennedy, research manager at Diabetes UK, also welcomed the findings.
But she added: "This is a very small, but interesting study that seems to suggest that if the mother has type one diabetes, the offspring have an increased risk of developing type two diabetes.
"Type two diabetes, however, is a complex
condition and there are a number of factors that can increase your risk of developing type two diabetes, including being overweight and not taking enough exercise. We look forward to seeing the results of more research in this area."