Visible crew/equipment: In the scene where John Travolta is racing Kirstie Alley to the hospital, there is one shot where a camera rigging is clearly seen mounted on the hood of Travolta's taxi in the reflection of the storefront windows.
Factual error: In the beginning sequence where they show the sperm first fertilizing the egg, it is biologically incorrect - only the head part of the sperm enters an egg, everything else stays on the outside and eventually dies off.
Continuity mistake: When Mikey is talking about his diaper being wet in the crib there is a rattle to his right which appears and disappears throughout the scene.
Other mistake: When James is taking Mollie to the hospital, he drives through a construction site and starts driving backwards, then does a 360 degree turn. In the aerial shot, you can see the skid marks from previous takes.
Audio problem: When James is rushing Mollie to the hospital, the camera is down the road from the taxi. James is saying something like, "You should do Lamaze breathing. It helped my sister," yet his mouth is not moving.
Revealing mistake: When Molly's mother is listening (to what she thinks is sex) outside the apartment door, the handle is shown on the right side of the door. But anytime after that the door opens from the left side. Both doors open on the left. (For some reason Molly has 2 front doors to her apartment).
Continuity mistake: When Molly and James are making out on her bed, she is hanging on to the bars of the bedframe and starts to daydream. You can see the scene is rewound and played and rewound several times before her daydream sequence.
Continuity mistake: When Molly takes Mikey to the Chubby Charles office to meet Albert, she changes his poopy diaper and slams it down on his new desk, rendering it junk. She then puts Mikey back on the floor, but never snaps the legs on his overalls. In the next shot, you see Mikey smashing Skeletor on the floor and his snaps are done, but when Molly picks him up to leave the office, they are undone again.
Continuity mistake: When Molly sees James for the second time and tells him that she's sorry for hitting him the other day, Mikey should've been about a few weeks or (at most) a month old, when in fact the baby portraying Mikey was much older (about 4-5 months old).
Factual error: When Mollie and James are bringing "Grandpa" to his new old folk's home, the shot that shows the address of the place says "Yaletown, Cambie St." This is a Vancouver address, where the movie was filmed, although it's supposed to take place in New York.
Continuity mistake: There is a car chase scene where they show him driving wearing sunglasses, then they cut back to him and he's not wearing them, then they cut back to him and he is wearing them...
Continuity mistake: When Molly is talking to her mother while she is on her excercise machine, her mother's NY Mets jersey is shown off and on her shoulder during the entire scene.
Continuity mistake: After Mollie was called by the elderly housing unit's administration, in the scene that she is cleaning up Grandpa's mouth, she is using a piece of a cotton roll and its package, which is cylindrical, is on the table. After a few shots, Mollie is still cleaning up Grandpa's mouth, but with a tissue, and the tissue's package, which is rectangular, is on the table too.
Continuity mistake: When Molly is being rushed to the hospital, there is a scene of a concrete worker who has to swing on the concrete slide to avoid getting hit by the taxi. The scene changes to a full view of the cab in the street and the concrete truck is nowhere to be seen.
Continuity mistake: When Kirstie Alley is getting Mikey ready to visit his biological father, a shot shows him from the front already dressed in the little lamb outfit, but then the next shot shows him from behind with Kirstie Alley still holding the outfit.
Continuity mistake: While Mollie is hitting James with the broom, a box of Cheerios falls off the shelf and gets wedged between the shelf and wall. Soon after they sit down the box of Cheerios is not there anymore, nor is it on the floor. Also, a white knick-knack on the shelf is now on its side and books that were not there before have appeared.
Continuity mistake: When James stands on the car hood to look for Mikey, his point of view shows Mikey standing about 30 yards away, but the shots of James running through the cars show him running much longer than that.
Continuity mistake: When Mickey visits his father he grabs a red doll and a small ball falls from it but in the next shot it's gone.
Continuity mistake: Mickey is drying his mom's hair with the hair dryer and hands her a toy phone. The way he grabs the phone changes between shots.
Continuity mistake: When John Travolta puts Kirstie Alley in bed and takes the baby in the cab for a ride. The baby tells him to take the bottle with him. He takes it and places it on top of the baby, in the next shot when he is going down the stairs to the cab, the bottle is no longer there.
