Oh, my.
I am about to open a can of worms with a bunch of rabbinic scholars.
Because the Tora prohibits humans from tattooing their body, from putting a brand anywhere on their person. (The only exception is when a bondsman or bondswoman refuses to leave one’s employ after the debt is paid. Then, they get their ears pierced. [Yes, this does mean Orthodox women use clip-ons—no pierced earrings for them].)