[[quoteright:220:http://static.tvtropes.org/pmwiki/pub/images/220px-The_Switch_Cover_191.jpg]]
[[caption-width-right:220:Best friend. Surprise sperm donor. What can go wrong?]]

2010 film written by Allen Loeb, directed by Will Speck and Josh Gordon, and starring Creator/JenniferAniston, Creator/JasonBateman, and Creator/JeffGoldblum.

Kassie Larson and Wally Mars have been best friends since childhood. Kassie, after years of bad experiences in dating, has decided to become a single mother through artificial insemination, much to Wally's protests. Nevertheless, she invites him to the insemination party wherein he gets drunk, accidentally spills the collection vial, and decides to replace the sample with one of his own. He blacks out and wakes up with no memory of this. Kassie leaves town, seven years pass, Kassie returns with her son Sebastian, and HilarityEnsues.

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!!This film provides examples of:

* [[ChekhovsGun Chekhov's Trait]]:
** Early in the course of the movie, Wally is shown to moan when eating good food. Later, Sebastian is shown to do the same.
** One surprisingly missed by the participants of the movie. Kassie and her sperm-donor have blue eyes and blonde hair. Sebastian has brown eyes and brown hair.
* BookEnds: Wally's voiceover and discussion regarding the "human race".
* ChildhoodFriendRomance: Kassie and Wally have been friends since childhood.
* DisposableFiance: Averted. Roland seems like a genuinely nice guy who just has the bad luck to come up against a Hollywood Romance.
* DoggedNiceGuy: To some degree, Wally from the beginning of the movie on.
* DuelingMovies: Filmed and released at the same time as ''The Back-up Plan'', also about artificial insemination and the complications of relationships with the sperm donor.
* TrailersAlwaysLie: At least some trailers for the film tried to push the idea that Creator/JenniferAniston was the lead character; she's certainly important but it's pretty obvious Jason Bateman is the real protagonist.
* VisualPun: The sperm donor is made to wear a [[HornyVikings Horny Viking]] helmet during the insemination party.
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