The correct answer is 'Liz'
Throughout the movie, Liz (Molly Sims) is primarily interested in having a baby with Gus, and she's very annoyed with his preoccupation with baseball. She is the only person sympathetic to him when she finds out that his friends have shunned him because he used to be a bully. At this point, Gus admits that the reason he is reluctant to have a baby is because he is worried that his kid will be constantly bullied because of karma paying Gus back for years of tormenting other kids. At the end of the movie, Liz tells Gus that she is pregnant and he is overjoyed.