Ovarian cancer is a common form of the disease
Consuming large amounts of milk may increase the risk of developing ovarian cancer, research suggests.
A study of more than 60,000 women found drinking more than two glasses of milk a day significantly upped the risk of the most serious form of the disease.
Dairy products have previously been linked to cancers, including those of the breast and prostate.
The research, by Sweden's Karolinska Institute, is published in the American Journal of Clinical Nutrition.
The researchers followed 61,084 women aged 38 to 76 for around 13 years.
During this time a total of 266 women were diagnosed with ovarian cancer, of whom 125 had serous ovarian cancer.
The researchers found women who consumed more than four servings of dairy products a day had twice the risk of serous ovarian cancer than women who had fewer than two.
They found that milk had the strongest link with ovarian cancer - those women who drank two or more glasses a day were at double the risk of those who did not consume it at all, or only in small amounts.
The reason why milk may increase the risk of ovarian cancer is unclear, but one theory is that lactose, a type of sugar found in milk, may overstimulate production of hormones which encourage tumour growth.
Diet element unclear
Dr Kate Law, of Cancer Research UK, said it was not yet clear how nutrients, or the amount and distribution of body fat affected the risk of developing cancer.
She said: "Previous research has also suggested that a diet rich in whole milk, yogurt and cheese may put women at higher risk of ovarian cancer.
"But the picture is far from clear, as other evidence suggests that women who drink skimmed or low-fat milk might have a lower risk of ovarian cancer."
Dr Law a major study, involving 500,000 people, was currently underway to try to assess the impact on diet on cancer.
"Until more is known about the specific components of diet that influence cancer risk, the best advice is to emphasize a balanced diet which includes plenty of fresh fruit and vegetables."
Around 6,700 women in the UK are diagnosed with ovarian cancer each year.