At the start of Season 6, legal proceedings have begun over Peter's refusal to agree to Carla's demands. Carla once again angers Peter by whining that he should just step aside and agree with her, and then shocks Peter by telling him that he may not be Reese's father, saying that she needed him to be a father at the time but Roger can fill that role in the future (back in Season 3, Carla hypocritically was angry when Peter asked if she was sure he was the father, implying he was a jerk for suggesting what turned out to be entirely true). Peter takes a DNA test to determine whether or not Carla's suspicions are true, but he chooses not to receive the results and decides he will be Reese's father regardless of biology. Carla does not respond to Peter's pleas to end the legal fight, but on Christmas Eve shows up angrily at the hospital with Reese and bitterly tells him "you win" and sarcastically thanks him for ruining her and Roger's lives, as Roger's boss booted him from the Germany-based promotion over the time he spent in court and they will have to remain in Chicago; Peter bluntly says he is sorry about the job but completely NOT sorry that his son will remain in the same city as him. In Season 7, Carla shows up anew to openly flirt with Peter, cause problems between him and new girlfriend Cleo Finch, and lie to Roger about Peter hitting on her to the point where Roger and Peter have an altercation in the ER.