Continuity mistake: When Allison is swimming with her nieces and Ben, she is sitting at the edge of the pool and you can see her stomach is normal and toned, but in the scene prior she meets with the gynecologist and you can see she has a fairly big belly. (00:54:45)
Continuity mistake: When Ben and Pete are talking about how children love bubbles, the bumps in Pete's shirt change from shot to shot. (00:58:50)
Continuity mistake: After Alison and Debbie aren't let into the dance club, they are sitting on a street curb. At one point, Debbie is shown with a cigarette in her hand near her mouth. The camera shot changes during mid-sentence and her hand is down at her side.
Continuity mistake: In the first shot of the ping pong match, Jay is holding his cup to his face. In the next shot it is sitting on the arm of the chair. (00:51:50)
Continuity mistake: In the bar scene after Allison and Ben first meet, they begin dancing, Allison's hair style changes throughout the night.
Continuity mistake: When Alison tells Ben she's pregnant and he starts talking about how she didn't notice he didn't have the condom on, the camera is on Ben and we see her hand going up to her face. In the next shot a split second later, her hands are both down in her lap.
Continuity mistake: When Ben and Pete are at a strip club in Vegas, Pete's dancer is wearing a plain, black g-string, but in the last shot the g-string has silver sequins and is tied at the side.
Continuity mistake: When Alison and Ben are having breakfast in the diner after their first night together, Alison's hairstyle changes throughout the scene. (00:18:50)
Continuity mistake: During the doctor's office fight Ben tells Allison it's a girl. Later, in the tub Allison refers to the baby as a boy. Stating "then he'll be wired for stress for the rest of his life." (01:24:03 - 01:50:44)
Continuity mistake: When Ben and Allison have dinner, in one shot Allison's hand is on her face, but in the very next shot it's down.
Continuity mistake: After the earthquake, when Ben and Allison are sifting through Ben's stuff that's all over the floor, Allison grabs the baby books and sees that Ben has not read them. The first shot showing the books has them in order of "What to Expect When You're Expecting", then "Expectant Father". In the shot immediately after that, the books have been switched, and the shot after that, the books are back to the first order.
