Naturally, given their joint inexperience in handling their own children, let alone anyone else's, disaster beckons. Mayhem, mess, tears, kicks in the shins and potty jokes are well documented in movies about infant miscare, but the additional presence of the childlike Marvin (Steve Zahn) here, recruited because of his fluency in Klingon (useful when dealing with Trekkie kids), and the well-selected child actors raise the level of the comedy.