My son specifically plays with the paper dolls he made. If you tell him to play with Barbie dolls, he will get mad at you and throw tantrums. He will draw different characters on a sheet of paper, color them, and cut according to its shape. He will do some role-playing game with his paper dolls.
He started with his obsession with paper dolls with the Real Steel characters. He will let the paper dolls fight. He will bring all of his paper dolls wherever we go. He is proud to show his paper dolls to everyone. He will introduce his paper dolls to all those people whom we meet and even tell a story about it. Whenever his paper dolls will have a tear, he will repair them by putting a scotch tape around it.
Some of his Real Steel paper dolls
His next obsession are the Team Fortress 2 characters. This time, he will copy the image from the Internet. Same with his Real Steel paper dolls, he will let the Red and Blu teams fight. Currently, my son is into Five Nights at Freddy's characters.
Sometimes I would get mad that his paper dolls were scattered all over the house. He has a special tin can for all of his paper dolls, but sometimes he would forget to pack them away.
You may wonder why I let my son play with "girls's toy". Personally, I do not see anything wrong with it. I want my son to develop his creativity and imagination that is why I let him do role playing games. He does not have any siblings, so doing role playing games make him feel that he has 'playmates'. Dolls are used by psychologists and behavior therapists in play therapy in drawing suppressed feelings of the child.
Playing with paper dolls is his way of exploring the things way beyond the tangible things around us. Playing with paper dolls is his way of having a 'playmate' as he is my only child. I may sometimes do not understand what kind of play he does with his paper dolls, but I do not restrict him for playing with such.
For mommies with boys out there, do not be afraid to let your kid play with paper dolls =)