> After disclosing the breach, 23andMe reset all customer passwords, and then required all customers to use multi-factor authentication, which was only optional before the breach.
As others have pointed out, there are also other options. Such as an email challenge when noticing high traffic, or damn, even when noticing a new login from a new device or IP that is unfamiliar. Many services do this all the time.
We’re talking about raw DNA data here that is accessible. You’d expect levels of security as implemented by banks if not better, not “Little Timmy’s first blog” levels of carelessness.