A majority of youngsters less than three years old can do it, with boys most often the ones attempting to unhook their seatbelts. "Young children might acquire the motor skills to unbuckle from restraints before developing the cognitive ability to understand the necessity of automotive restraints," said Dr. Lilia Reyes, a clinical fellow at Yale and co-author of the report.

More than 40 percent of children who are able to unbuckle the restraints are doing so while the car is moving, prompting many parents to pull over, reprimand and then re-buckle the child, according to the study. Better engineered seatbelts, or even an alarm, might be part of the solution, Reyes added.