Sympathy Bump?

It's widely known that tons of husbands gain weight when their wives are preggers - i believe they refer to this as "sympathy weight". Well, Nate doesn't really have this prob, but Ben does. He has not gained weight, but he does think he's pregnant. He will walk around saying things like: "My tummy hurts cause my baby sister is kicking me" or I'll ask "where is your baby sister?" and he will reply "In my tummy" while he starts rubbing his belly. I guess he's just immitating his mom, who apparently needs to be very careful about what she says and does!