Less than a week after the Vatican issued a document raising ethical concerns about fertility treatments -- among various other biomedical developments -- a new study has highlighted risks associated with drugs that help ovaries release at least one egg per month.

Such drugs don't normally pose an ethical challenge; after all, their goal is to treat the disorder of anovulation and help a woman's body function normally.

But a new study in the American Journal of Epidemiology finds that the use of such drugs -- a widely used one is called clomiphene -- increases the risk of uterine cancer by three times; and more than eight times for women who took more than a year to conceive.

The researcher also found a link, though less clear-cut, between use of the drugs and cancers of the breast and ovaries.

For the moment, the researcher recommends follow-up studies and long-term screening of women who have taken such drugs.