MAK
From Celeb Dirty Laundry:
General Hospital spoilers indicate that Carly and Nelle could in fact be sisters but if you had to choose, which man would you like to see as Nelle’s father, Jerry Jacks or Roy DiLucca? Either way, this could explain why Carly is so drawn to Nelle and how Nelle would have been compatible for the kidney donation. She would be Carly’s sister, and Josslyn’s aunt.
From Soap Opera Spy;
Nell could be Jax’s daughter, who he has kept secret from Carly? Is this why she was such a great match or could she be the daughter of the infamous Jerry Jax.
When Morgan reached out and kissed Nelle she pushed him away as if she was repulsed. Could this be because she suspected he was her brother?