Kinder and the seven other baby geniuses are shocked that Whit and Sylvester switched places at the mall, but Dr. Kinder becomes excited and begins to see this as an opportunity to do a cross-evaluation on the twins. However, when she comes to Dan Bobbin's place, she realizes that Dan can understand babies. After the attempts to retrieve Sylvester fail, Dr. Kinder decides to move the research facility to Liechtenstein, and they have no choice but to make Whit the only normal baby to be raised in this research facility until they can find a possible way to get Sylvester back to her research facility. The babies at Bobbin's place hypnotize Lenny, the bus driver, to drive to Dr. Kinder's research facility. Once at the research facility, Sylvester goes to the control room to set the robots from the theme park on the lab scientists. When the Bobbins return home, their natural daughter Carrie tells her father that the children are in Dr. Kinder's research facility. At the end of the fight, Dr. Kinder captures Whit and takes him to the helicopter pad on the roof. Robin and Dan chase them to the roof, where Dr. Kinder reveals that she and Robin are not related and that Robin was adopted at age 2. After Dr. Kinder is arrested by the police, Sylvester and Whit come together on the roof to cross over. Dan and Robin adopt Sylvester. Dan is still curious about the secrets of life; but, as the twins have crossed over, they no longer know those secrets. Carrie, their sister, doesn't reveal anything (just giving her father a Sly smile) because adults are never meant to know their secrets. Cast Kathleen Turner as Dr. Elena Kinder Christopher Lloyd as Dr. Heep Peter MacNicol as Dan Bobbins (the biological father of Carrie and adoptive father of Whit & Sylvester) Kim Cattrall as Robin Bobbins, Dan's wife (the biological mother of Carrie and adoptive mother of Whit & Sylvester) Dom DeLuise as Lenny, who is a janitor and sitter for Dan and Robin. Ruby Dee as Margo, Dan and Robin's housekeeper. Kyle Howard as Dickie/Ice Pick, a teenage guru of the group in Dan and Robin's family. Kathleen Freeman as Lenny's Noisy Neighbor (uncredited) Jim Hanks as Goon Ray Sam McMurray as Goon Bob Dan Monahan as Reporter Leo, Gerry and Myles Fitzgerald as Sylvester & Whit (Voiced by Miko