Doctors frequently prescribe one treatment over another without any evidence to know which option works best, and they don't have to tell their patients that they're essentially guessing.

But when researchers study which commonly used option is best, they're supposed to outline all the risks.

A says a controversial study of didn't properly do that, setting off debate about how much patients really need to know when enrolling in this kind of research.

Some critics say full disclosure is an ethical must. But others say that could mislead patients into thinking research is riskier than their own doctor's best guess.

Federal health officials convened a meeting Wednesday to hear from the public on how to handle the disclosures.