The obvious answer is that self-reported race is correlated with many biological traits throughout the body. This is already known. It's no surprise that ML can

The obvious answer is that self-reported race is correlated with many biological traits throughout the body. This is already known. It's no surprise that ML can detect those differences. If somebody's self-identification is abnormal (doesn't know their ancestry, say), then sure, the AI might see through it. Conventional measurements could see through it too.