In settings where superpowers, magic, or otherwise preternatural abilities are already abundant, there remain those who stand out by having rare and specific superpowers not found beyond their family tree. Generally only applies in a setting where it's theoretically possible to learn superpowers, as otherwise this just becomes a case of Superpowerful Genetics.
- Naruto: The various kekkai genkai, usually translated as 'bloodline ability'.
- Harry Potter: Metamorphmagi. I seem to recall another family-linked ability, but someone will have to help me out with that.
- Real life: We can all learn gymnastics, but only some people are double-jointed, as this runs in the family.
Hello, Unknown Troper. You'll need to get known to lend a hand here.