It's a bit like the old adage that we should not judge a book by its cover. The outside often does not provide any clues into the content or worse, it could bias an observer's opinions about what they would find inside if they chose to engage with the material.

Its akin to judging a man by the color of his skin instead of by the content of his character.

Thanks for your comment that clarifies how genetics provides a much more granular window into an individual than any physical characteristic taken by itself can provide.