When the consumer genetics industry came before the US Congress in 2010, Phil Gingrey, a Republican congressman from Georgia and a former obstetrician/gynecologist, worried how people would react if they learned their risks for serious diseases without the involvement of a doctor. "You've got a lot of hypochondriacs out there," he said famously at the Congressional hearing, "and we're going to make maniacs out of them."

But a small study by researchers from 23andMe and Stanford University has found that people who learned for the first time through 23andMe's Personal Genome Service that they harbored BRCA mutations linked to a heightened risk of breast and ovarian cancer definitely didn't turn into maniacs.

The study, published in PeerJ this week, involved 32 mutation carriers and 31 mutation negative controls who are 23andMe customers. After phone interviews with study participants, researchers led by 23andMe Senior Medical Director Uta Francke found that among the 25 participants — 11 women and 14 men — who received an "unexpected' results, none of them reported feeling "extreme anxiety," four said they had "moderate anxiety" that went away after a while, and five women and six men said they felt "neutral."

Among the non-carriers, learning their BRCA didn't make them believe that they were free of cancer risk. All but one mutation-negative participant thought that her cancer risk was reduced, but most participants in this cohort seemed to understand that there are other genetic and environmental factors that could cause breast and ovarian cancer.

The three BRCA mutations reported by 23andMe's Personal Genome Service are highly prevalent in those of Ashkenasi Jewish decent. Based on the lack of emotional distress seen in this survey, the study authors believe that 23andMe's testing service can serve as a broader screening tool for individuals of this origin.

The findings of this survey are in line with similar investigations that have found that genetic test results don't cause consumers to irrationally freak out. For example, a few years ago researchers from the Scripps Translational Science Institute surveyed the reactions of more than 2,000 people who had learned their genetic predisposition for 23 diseases and conditions through Navigenics' Health Compass. The survey revealed that the majority of study participants reported no significant changes in levels of anxiety, dietary fat intake, or exercise after receiving genetic test results.

Of course the 23andMe survey is significant in that it's focused on a specific set of gene mutations that confer five times greater risk of breast cancer and up to 30 times greater risk of ovarian cancer than normal in women who harbor them. As such, a number of mutation positive women in the study were moved to take some action.

For example, among the 11 women who learned they were mutation positive for the first time through 23andMe, one had a prophylactic mastectomy, three planned to have mastectomies, three had oophorectomies, and four planned to have oophorectomies after they had children. Five women said they wanted to get breast exams or breast imaging tests, and seven said they would continue to monitor their health through regular breast exams.