Laura (wife no. 2 is step mom to my daughter. When she was young (3 or 5) she called her mom mom and Laura mamma. I asked her why and she said "we have no steps in our house and Laura sounds too formal. It stuck to this day. No mart what, her father needs to take a bite of reality and grow up and realize it tales more than biology to be a father. I say let her call each man what she wants.