People who seek whole-genome testing have found, until now, that it's an all-or-nothing affair. Either they agree to learn all the results and what they indicate about their health and inherited risk for diseases, or they don't do it at all.

This has an ethical simplicity, because doctors don't want to play God and decide what information patients should receive. But researchers at the Mayo Clinic have been interviewing patients and discovering that they would prefer a more nuanced approach. "[Patients] say that being able to have a say in what they learn or don't learn is really kind of important," said Jennifer McCormick, a Mayo expert on bioethics and genetics.

In an article in Mayo Clinic Proceedings, McCormick and her colleagues support revised guidance by the American College of Medical Genetics and Genomics.

The guidance would give patients more authority over genetic findings "incidental" to the diseases from which they are suffering.

In 2013, guidance had fueled the all-or-nothing approach, because the college required the examination of more than 50 specific genes and the placement of results in patients' medical records. Doctors felt compelled to discuss these results once they were placed in those files.

Circumstances dictate the choices of patients, who receive whole-genome testing at Mayo whether they are cancer patients seeking better treatment or "diagnostic odyssey" patients with mysterious symptoms, McCormick said.

Cancer patients might not have the strength to learn, for example, that they have a certain mutation that increases their risk for Alzheimer's disease. "We've had oncology patients … who say, 'I can't handle anything else. I'm dealing with this cancer,' " McCormick said.

Others have worried about the effect of genetic results on health insurance benefits, or questioned why they would want to know about risks of diseases such as Alzheimer's for which there aren't cures. But that is hardly the only viewpoint.

Even if Alzheimer's is incurable, some patients have said they might make life changes if they knew they were at increased risk.

An individualized approach presents challenges for the future, though. For example, should patients give more than 50 prior consents on each required genetic test? "That's something," McCormick said, "we're all struggling with."