How is a NERD Lemon (or any other "line"), that is most likely being bred to selectively picked normals or other mutations considered inbred?
Lines are established by very selectively chosing what they are bred to, to enhance the morph.
My NERD Lemon has always been bred to carefully selected normals when I want to make more Lemons - none related to him, and has produced babies even nicer than him BECAUSE of the females I selected for him.
Ah well, C'est la vie!