There are several studies about the association between milk and cancer. The most substantial evidence available suggests a link between dairy and an increased risk of developing prostate cancer or ovarian cancer. Scientists don’t know the exact relationship between dairy and those types of cancers yet, but we already know that neither the dietary fat nor the calcium in milk is the cause. The problem is that those are all observational studies that might indicate correlation but which do not prove causation. Still, if you have a family history of those types of cancer, it might be worth removing dairy from your diet.