In some states, a child can sue his parents for negligence. (See, i.e., Gibson v. Gibson (1971) 3 Cal.3d 914.) The traditional rule is that a child cannot sue his parents for negligence.
If the negligence of a parent combines with the negligence of another person, and the result is injury to a child, some states hold that the other person is 100% liable for the child's injuries, and the parent is not liable for any of it. (See, i.e., Smelser v. Paul (2017) 398 P.3d 1086 (Washington Supreme Court).)