Kate Holbrook (Tina Fey) explains the rules to her surrogate, working girl Angie Ostrowiski (Amy Poehler), in “Baby Mama.”

K.C. Bailey—Courtesy Universal Pictures

Kate Holbrook (Tina Fey) explains the rules to her surrogate, working girl Angie Ostrowiski (Amy Poehler), in “Baby Mama.” K.C. Bailey—Courtesy Universal Pictures