JINAN, China—Ning Wentao sat stoically with four electrodes taped to his stomach as a nurse gradually raised the flow of current to his abdomen.

Not an experiment or a treatment, the electric shock biting into Mr. Ning was meant to simulate the sensation of childbirth. A 28-year-old expecting father, Mr. Ning says he agreed to try it out of solidarity with his wife, who is due on Christmas.

Having...