Continuity mistake: When Schwarzenegger's urine is tested for pregnancy, the colour of the contents of the vial does not stay the same for two consecutive shots.
Audio problem: There is a scene in the lab where Arnie is explaining his pregnancy to Emma. The shot cuts to a side-on, rear shot of Arnie and it is very clear his mouth or jaw isn't moving and yet you can hear him talking.
Continuity mistake: While chasing Alex out of the hospital, Diana knocks into a man who is on roller blades and he falls over. Yet in all shots afterward he is not on the floor and we never see him get up.
Revealing mistake: When Alex throws Banes at the lab, you can see the stunt double falling for him.