Consumers should not have to make “Sophie’s Choice.”

But every day, they do.

A shocking abundance of vehicles feature more shoulder harnesses than head restraints.

The list extends from mainstream sedans such as the Ford Fusion, to the trendy Mazda CX-7 soft-roader, to the luxurious Cadillac SRX cross/utility.

The deficiency occurs in rear seating positions, which begs the grim question: Who goes unprotected?

In most families, this dubious honor is won by default. The youngest get shortchanged because, well, they’re usually the shortest.

For them, seat backs can rise to the challenge and, in event of a rear-end collision, function as a head restraint.

But as every parent knows, they don’t stay small forever.

The U.S doesn’t compel auto makers to equip every seating position with a head restraint. So they don’t.

The prevailing wisdom is, ironically, safety. Consumers complain head restraints block their view of traffic, a Ford engineer tells me.

Funny we don’t hear an outcry from, say, Audi owners. European regulations force auto makers to outfit their vehicles with a head restraint for every seating position.

Meanwhile, Audi does not omit the devices when the vehicles are shipped here. But the reverse is not always true.

Chrysler Group’s plant in Belvidere, IL, is the sole source of its wildly popular 5-passenger Dodge Caliber small car – one of the auto maker’s best-sellers outside North America last year.

Units built for the domestic market have four head restraints. The European version has five.

And this is not a new practice.

In 1999, Toyota went to trial in response to a suit filed by an Oklahoma teenager who was a passenger in a Camry. She was left paralyzed after a crash because the lap-belt she was wearing nearly cut her in half.

A jury heard that Australian-market Camrys featured five shoulder harnesses, while those destined for the U.S. had four shoulder harnesses and one lap belt. Toyota settled out of court.

Richard Denney, the girl’s lawyer, who notes the dearth of available lap-belts today, suggests cost-savings is a major motivator for skimping on safety equipment.

National Highway Traffic Safety Admin. studies suggest auto makers stand to save about $6 per vehicle if the number of seats exceeds the head restraint count by one.

Why doesn’t NHTSA adopt the European mandate? Because government can’t stick its nose everywhere.

Degree of risk is a key consideration, which explains why NHTSA wants to see electronic stability control on all new vehicles by 2011. Stability control mitigates rollovers, and rollovers often mean death.

Head restraints protect against whiplash. While debilitating and costly – NHTSA says the quarter-million cases each year have an economic impact of about $2.7 billion – whiplash pales when compared to a rollover’s consequences.

Still, the mental picture of your cherub-faced daughter’s head snapping backward like a crash-test dummy is chilling.

That said, summer is upon us. Time to ice the cooler, strap the canoe to the roof rack and decide which one of your children is expendable.

Happy motoring.