As the cost of medical insurance keeps growing rapidly, more and more New Jersey companies are starting to charge their employees, who smoke or are overweight, more for their health insurance.

Zero Creatives, Getty Images

Some are wondering if the trend is dangerous, and where it will stop.

"You can't blame employers for being concerned about employees behavior that affects health care costs, but when employers start telling people what they can and cannot do in their private lives, and penalizing them when they don't comply - who wants to live in that kind of world," said the President of the National Workrights Institute in Princeton, Lew Maltby.

He points out under Obamacare and HIPAA rules, companies can dramatically increase health care costs for workers, who smoke or are overweight, by as much a 30 percent of the cost of the insurance. That could be a lot higher than their company is paying for the coverage.

Maltby said there is nothing that we do in our private life that doesn't affect our health.

"Do you ride a bike to work, or drive in a car? On vacation do you sit on the beach or go skiing? Your employer could, under this precedent, ask you how many people are you having sex with and who they are and are you practicing safe sex, cause that'll save them money on the health care plan too," he said.

He adds this may sound like a joke, but it's not.

"A dollar an employer saves by regulating your sex life is just as real as a dollar they save by penalizing you for smoking or drinking. Not all slopes are slippery, but this slope really is," Maltby cautioned.

Maltby suggests the first step employers should be taking is to try and help employees develop healthy habits, instead of looking for ways to penalize them.