Unlike other ghouls, Born Ghouls are not mutated humans, but were actually born into ghoul-dom. Through cruel experimentation on humans by Dr. Sebastian at the Reservation, these ghouls gestated and were birthed.
Reveling in their infrequent success (the ghoul procreation experiments have a 2% success rate), Dr. Sebastian and Dr. Willem Clark keep their Born Ghoul progeny close at hand and comfortable. To them, the Born Ghouls represent the future of the ghoul "species", and they will do everything in their power to make sure their "children" are well taken care of. There are only three Born Ghouls, including Measles and Belle. At first glance Born Ghouls look like any other ghoul, but a closer inspection reveals that their lesions, exposed bone, and hair patches are very uniform and look like they even serve some kind of purpose. On top of that, these ghouls are a little tougher, a little stronger and a little faster.