The genetic testing company 23andMe has won FDA approval to test for some mutations in the BRCA gene. While some genetic mutations in that gene have been shown to be strongly indicative of the development of breast cancer, the company is only testing for a few of those mutations. There are a lot of other breast cancer-causing genetic defects lurking out there.
Some doctors are concerned that someone getting results from this test might be misled into thinking they are not at risk for the disease, when in fact they harbor some other genetic mutation that is causative for breast cancer.
Anyone taking this test should do so with the knowledge that it only offers limited insight into cancer risk. Genetic testing that is predictive of health problems is still in its early stages, and there is a lot we still have to learn.