There was actually a research paper where they figured they could predict if people drink wine or beer with a CNN that looks at knee X-rays. Turns out that part of their data is from beer drinking regions, and another part from wine drinking regions, and that the photos are just ever so slightly distorted depending on which physical machine they were made with.

The paper pointed that out, it's whole propose was to show how much bullshit you can use AI for if you are not careful what you train it with.

There were many other examples in this paper of what they can predict just from people's knee X-rays. They had all non-medical explanations such as the one above.