Originally posted by: Stoopider
Sakura's parents. Most probably civilians. Probably like Ino's mom. (takes care of flower shop).
Helping out with the economics of the village. Rather than its protection.
That was my theory, and would explain why she's so weak. Her parents are normal people, not descended from ninja of Konoha like the others are. Most likely likewise with TenTen and Lee's parents. They are ordinary people without the talents to be ninja.

As for the parents you did see, I would suspect their abilities already reveal potential future bloodline limit techniques.

After all, the parents are using more potent versions of their childrens' techniques and isn't that what starts the process that ultimately becomes a bloodline limit?