the baby -- plot hole? (spoilers)
So, when Dory brings up the fact Chantal was pregnant to her ex, Gavin, he's all HOW DID YOU KNOWOWOOWOW. And when she asks who the father of the baby was, he said "even if I knew, what good would it do telling you" etc.
But then at the end, it's revealed Chantal was not actually pregnant and the baby photo was her sisters' baby. So why did Gavin react like that?