Nielsen ex rel. C.N. v. Wade ex rel. B.B., 370 P.3d 925

A 4-year-9-month-old boy threw a toy dolphin that struck his babysitter (Ms. Nielsen) in the eye, causing total vision loss in that eye after a prior cornea transplant.
Ms. Nielsen sued the boy (negligence) and his parents (negligent supervision); she conceded no evidence supported parental negligence.
The district court granted summary judgment for the parents but denied summary judgment as to the child, concluding a four-year-old could potentially be negligent.
The Utah Supreme Court granted interlocutory review of the denial of summary judgment as to the child and reviewed the legal question de novo.
The majority adopted the Restatement approach and held as a matter of law that children under five cannot be held liable for negligence, reversing the district court and directing summary judgment for the child.
A dissent would have preferred a tiered, rebuttable framework based on contemporary cognitive science (categorical immunity under age three; presumption of incapacity ages three–seven; capacity presumed at eight+).

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether Utah common law recognizes a minimum age below which a child is conclusively incapable of negligence	Nielsen: a 4‑year‑old may be liable; issue should be fact‑specific	Defendant: Utah precedents bar negligence findings for children under seven (or at least under five)	Court: Children under five are, as a matter of law, incapable of negligence; reverse and grant summary judgment for the child
Whether Utah follows the Illinois rule (conclusive incapacity <7; rebuttable presumption 7–14)	Nielsen: oppose fixed cutoff; prefer case‑by‑case analysis	Defendant: Illinois rule applies	Court: Rejected adopting the Illinois rule in full; earlier dictum to that effect was not controlling
Proper standard for children aged five and older	Nielsen: capacity should be fact question for jury	Defendant: earlier cases support presumption of incapacity for certain ages	Court: For children ≥5, capacity is for the fact‑finder unless no reasonable jury could differ
Whether Herald v. Smith establishes a binding rule that <5 cannot be negligent	Nielsen: Herald uncertain or inapplicable	Defendant: Herald supports immunity for ~5‑year‑olds	Court: Treated Herald as controlling precedent supporting a <5 dividing line and relied on it among other cases to adopt the <5 rule

Nelson v. Arrowhead Freight Lines, 104 P.2d 225 (Utah 1940) (earlier dictum referencing the Illinois age rule but not controlling)
Mann v. Fairbourn, 366 P.2d 603 (Utah 1961) (held capacity for negligence of a 5½‑year‑old is a factual question; rejected Nelson dictum)
Donohue v. Rolando, 400 P.2d 12 (Utah 1965) (treated young children’s capacity as a jury question unless beyond dispute)
Rivas v. Pacific Finance Co., 397 P.2d 990 (Utah 1964) (held capacity of a child just under six was for the jury)
Kilpack v. Wignall, 604 P.2d 462 (Utah 1979) (applied a rebuttable presumption regarding a seven‑year‑old’s contributory negligence)
Herald v. Smith, 190 P. 932 (Utah 1920) (concluded a 4‑year‑10‑month‑old could not be charged with contributory negligence; treated as a legal signpost for the <5 line)
Roper v. Simmons, 543 U.S. 551 (2005) (cited as an example of courts drawing bright‑line age rules for policy reasons)