23andMe's breast cancer test may create false sense of security

Women can now buy a test telling them if they carry variants of the BRCA1 and BRCA2 genes that raise their risk of breast cancer. That sounds like a welcome advance in medical technology. But the particular variants identified are mostly confined to Ashkenazi Jewish women and are very rare in the general population. If women buying the new test don’t understand that, there is a risk they could be lulled into a false sense of security if they test negative.

The test is being sold by 23andMe,…