Along the way, the couples have come to question just what is male behavior and female behavior, noting how quickly their preconceived notions dissolve once they depart from assigned roles. The men echo generations of housewives, voicing concern over a loss of earning power and car pool-induced torpor but also pride in their nurturing roles. The women describe themselves as competitive, tough and proud of every dollar they bring in.

“We’re almost like an opposite ’50s couple,” said Mr. Skinner, Nicole Black’s husband. “I’m staying at home, I do the dishes, I do the laundry, I do everything the housewife does. I’m just a dude.”

Not every marriage proceeds as smoothly. One female banker told colleagues that she recently became irritated with her husband, who works part time, telling him, “I wish I had a wife.”

“You can get one when I can get one,” he replied.