Wally (Jason Bateman) and Kassie (Jennifer Aniston) are friends who end up with more in common than they bargained for in the artificial insemination comedy The Switch. (Walt Disney Studios)

The Switch begins on a crowded New York subway car, where hunched narrator Wally Mars (Jason Bateman) is surveying the horrible and miserable folk around him, silently bemoaning their collective lot as the ones who will never know the feeling of true love.

Just when The Switch should be embracing its black-heartedness, the film opts for a plotline that evokes every cornball romance ever broadcast on the W Network.

Any doubt that this sourpuss equities analyst is a Woody Allen surrogate is assuaged as Wally plunks himself down at a lunch date with best friend Kassie (Jennifer Aniston), shares cell phone pics of the growth he is convinced is a tumour and insists “I’m not pessimistic, I’m a realist.” The light to Wally’s dark, the 40-year-old Kassie explains, like a cheerful infomercial, that her life “is in session!” Sick of waiting for the right man to come along, she has decided to find a sperm donor to father her child.

Thanks to Bateman’s economical reaction shots, we know that this announcement doesn’t sit right with him. Wally has been secretly pining for Kassie, but soon finds himself showing begrudging support at a mock “insemination party,” where Madonna’s Papa Don’t Preach blasts on a boom box and drunken revelers are covered in sperm confetti. Kassie’s pre-selected stud of choice — the good-natured, vacuous Roland (Patrick Wilson) — has just provided his donation in a little plastic cup. Before the night is through, Wally gets blotto enough to think that substituting Roland’s sperm sample with his own is a good idea.

As politically incorrect and icky as this scene is, Bateman has the physical-comedy skills to pull it off, and the actual switch is one of the sole funny moments in The Switch. This twisted setup is inspired by Jeffrey Eugenides’ offbeat short story Baster, and the movie’s first half hour suggests that what’s in store could serve as a weird antidote to all the fluffy-kitten sentiments of the standard rom-com.

But just when The Switch should be embracing its own black-heartedness, screenwriter Allen Loeb chickens out, flash-forwarding seven years and opting for a plotline that cobbles together bits from every cornball romance ever broadcast on the W Network on a Saturday night.

A dinner at a Chinese restaurant reunites Wally with Kassie, who now has a six-year-old son named Sebastian (Thomas Robinson, cribbing many moves from the Jerry Maguire cute-kid playbook) in tow. One look at the little rug rat — with his inquisitive eyes, cranky demeanour and burgeoning hypochondria — and it’s clear that the precocious youngster possesses some of Wally’s DNA.

Kassie's pal Debbie (Juliette Lewis) hosts an insemination party in The Switch. (Walt Disney Studios)

The fact that it takes the characters in the movie forever to figure this out is implausible, which is forgivable in a genre not known for its realism. But as Wally struggles to remember what happened on that drunken night seven years before, everything else in The Switch begins to feel painfully rote. It’s all there: the warbly, leading soundtrack; the requisite scenes of Wally bonding, About a Boy style, with the alienated child; the flat, unimaginative staging; the will-they-or-won’t-they dynamic between the best friends.

It is in this last, romantic storyline that The Switch proves most disappointing. Asking viewers to believe that Wally and Kassie would contemplate being more than buddies is ridiculous, since the two leads have zero chemistry and the script can barely explain why they’re even friends. Save for one shared college memory involving C& C Music Factory, these two have nothing in common, and spend so much time bickering, you’ll be grateful for the moments when the exasperated Kassie demands they take a “time out.”

This phoney material is tough on the lead performers. While Aniston fares well in her moments as a single mom, she’s a bit shrill and chirpy around Wally. Who can blame her? I found myself tuning out and basking in the otherworldly glow of her hairdo and makeup. She gets off easy compared with Bateman, who must carry the movie and finds himself saddled with its most saccharine scenes. It’s a tribute to his skills as a character actor that he makes Wally likable, hinting at a credible sadness beneath the misanthropic exterior.

Bateman almost makes you forget that what’s happening around him has gone off the rails, and he finds a terrific foil in Jeff Goldblum, who pops up in a few scenes as Wally’s confidante Leonard. As written, this character could’ve turned into a sidekick as predictable as everything else in The Switch, but Goldblum gives Leonard a strange, cool-cat grace. Whether he’s goofing on the piano at a kid’s birthday party or scarfing down chocolate bars during a workout on the treadmill, Leonard is a hoot, and a true original. Neither horrible nor miserable, he knows exactly who he is — a comforting thought in the midst of a movie suffering from a major identity crisis.

The Switch opens Aug. 20.

Lee Ferguson writes about the arts for CBC News.