I shouldn't be harsh on The Switch because it knows what it is: a dumb romantic comedy, operative word: dumb. In a nutshell, a woman who has a straight male best friend will end up with said friend regardless of how ill-suited they are. This will especially happen when there is another man, usually better-looking or smarter or wealthier or more stable either financially or mentally, is also courting our heroine. The Switch could have done good things if it hadn't been bogged down with some rather horrible people.
Kassie (Jennifer Aniston) has reached that critical age of 40. She is unmarried and knows she has a limited window to have a child. Therefore, she opts for artificial insemination. This does not sit well with her hypochondriac, neurotic platonic friend Wally (Jason Bateman), who is doing voice-over work in The Switch. Wally has no tact: he sees nothing wrong in showing pictures of his penis to ask if there's an unhealthy growth, is hyper-sensitive (being called a beady-eyed little man-boy by a homeless man causes him endless worries), moans when he eats, is controlling, and selfish: all of which cause a break in their friendship.
Nonetheless, she is undaunted, and her best friend Debbie (Juliette Lewis) is throwing an insemination party. At said party, people will eat drink & be merry before Kassie goes and gets knocked up privately. Despite their slight falling out Wally is invited, where he gets plastered. Naturally, the donor is there to: a married man named Roland (Patrick Wilson) who is doing it for the money and noted, with his wife's consent.
It really is all for naught: in Wally's inebriated condition, he literally spills it, and with the insemination a few moments away, must rise to the occasion with a little help from Diane Sawyer: don't ask. With the insemination successful, she opts to leave New York. Seven years later, she decides to move back to the city, bringing her son Sebastian (Thomas Robinson). The curious thing about Sebastian is that he is a hypochondriac, a bit of a pessimist, and moans when he eats. It takes a few moments for Wally to realize that Sebastian is his son. It takes longer for both Roland (who by now is free from his wife and interested in Kassie) and Kassie herself to figure it out. Actually, Kassie never figures it out: Wally has to confess the truth.
Here's where The Switch goes terribly, terribly wrong: Wally is such a loathsome character in his neuroses and his hyper-controlling manner with Kassie that no one in their right mind would want to be around him, let alone end up with him. For example, at a party Kassie sees someone she is interested in, both romantically and in providing sperm. Wally locks her out on the balcony, tells the guy she's either a nut or a slut (can't remember which) and sends him on a wild goose chase. And we're suppose to like him?
Allen Loeb's screenplay (based on Jeffrey Eugenides' short story "Baster") doesn't try anything new or interesting with the premise. You have a standard imagined love triangle (between Kassie, Roland, and Wally) and remarkably stupid people. I did wonder why Kassie never noticed that her son moaned when eating just like Wally did for example. It's also now a standard in romantic comedies where the woman will not choose a man who appears to be better.
One thing that I found rather creepy and slightly unbelievable is the Insemination Party. I figure this was the only way they could find to get Wally's sperm into the film, but it only came off as almost grotesque as opposed to funny. One would think the sperm would be protected, instead of just lying around the bathroom. I thought it would have been funnier if Wally had donated years before and Kassie had unwittingly received his sperm unbeknownst to both, but I digress.
Granted, as played by Wilson, Roland is a bit dim himself, more interested in athletics than intellectual pursuits. However, the film would have been more interesting if Roland had been a more well-rounded character. The Switch would have been more interesting if any of the characters had been more well-rounded. However, to his defense Wilson made Roland a remarkably pleasant character, at least in the beginning when we could understand his motivation in donating sperm. It was only when he returned that he became blank (no pun intended) and Roland just proved to be a mere impediment to Wally's thwarted hopes for Kassie as opposed to taking a role in his son's life.
Neither Aniston or Bateman were interesting because one couldn't believe they would want to be around each other, let alone friends. I'll say that Bateman did a good job if he wanted Wally to come off as a touch stalker, a pessimist who brings everyone down. Aniston has mastered these types of film characters (woman in search of a man who finds Mr. Wrong is Mr. Right), but she has not expanded her range much. It would do her well to get away from these types of films.
If Wally had been more sympathetic, more pleasant, had a genuine yearning for fatherhood or a woman instead of being a down, unhappy, even cruel character, The Switch would have been light fare. However, his character makes the experience quite unpleasant. At one point, I begged Kassie in my mind to stay with Roland even though I knew she wouldn't, and kept wondering why in modern-day romantic comedies women appear to go with a totally unsuitable man.
The Switch is predictable, which makes it unfunny and slightly unpleasant, with people going through the motions attempting to make us laugh and failing at it. No one would, in the end, want to be in this Wally World.