"The Switch" is a 2010 romantic comedy film starring Jennifer Aniston and Jason Bateman. The film centers around Kassie Larson (Aniston), a 40-year-old woman who decides to have a baby on her own using a sperm donor. Her best friend, Wally Mars (Bateman), disapproves of the plan and secretly harbors feelings for Kassie.
At Kassie's insemination party, Wally drunkenly switches the donor sperm with his own without her knowledge. Kassie moves to Minnesota and raises her son, Sebastian, on her own.
Seven years later, Kassie returns to New York City and reunites with Wally, who now realizes that Sebastian is his biological son. He struggles with whether to tell Kassie the truth, fearing it will ruin their friendship.
Meanwhile, Kassie begins dating a charming man named Roland (Patrick Wilson), and Wally's jealousy grows as he tries to win Kassie's heart. In the end, Wally confesses his secret to Kassie, who is shocked but ultimately forgives him. The film ends with Wally and Kassie realizing their love for each other and starting a romantic relationship as a family with Sebastian.
"The Switch" received mixed reviews from critics but was praised for its performances, particularly Aniston and Bateman's chemistry. The film explores themes of friendship, parenthood, and the complexities of relationships.