Jennifer Aniston plays Kassie, a single-women whose concern for her biological clock leads her to the ‘only’ plausible action – artificial insemination. Wally Mars, played by Jason Bateman, is the neurotic, love-sick friend who, unsurprisingly, isn’t so supportive of Kassie’s decision. Why choose the artificial option when the real thing is standing right in front of you?
Kassie sees Wally as no more than a close friend and confidant, and so, on the night of the ‘insemination party’ we meet the handsome Roland (Patrick Wilson), the man the soon-to-be mother has chosen to provide the seed.
As expected, things get complicated when the crestfallen Wally Mars is forced to, literally, take matters into his own hands. Drunk and on the bathroom floor, we find the best-friend ‘making the switch’.
Seven years after a happily pregnant Kassie moved to Minnesota, she finds herself back in New York with her son Sebastian (Thomas Robinson), who shares uncanny physical and psychological traits with bachelor Wally. The young-boy is a hypochondriac that uses big words while worrying about the world. To say Sebastian and Wally are similar is an understatement. As their relationship grows it soon becomes quite clear that Wally is the sperm donor.
So with his lifelong dream within arms reach, Wally breaks the news to Kassie. What unfolds, tests the boundaries of their friendship but Wally hopes Kassie can see beyond the hurt and find it in her heart to forgive the father of her son.