It has been almost five years since Jennifer Lopez (2005's "Monster-in-Law") has headlined a major studio release, and in the interim her star has fallen to dramatic lows. How can one know this? Because out of all the hundreds of films being made in Hollywood each year, the best she could find for her comeback role is "The Back-Up Plan," an absolutely odious, tone-deaf romantic comedy that wouldn't even pass muster on the Lifetime Channel's worst day. Forget "Gigli," her infamous 2003 film with Ben Affleck that wasn't so much bad—actually, it's rather underrated—as it was a victim of unwarranted negative press. "The Back-Up Plan" is Lopez's new—and this time, well-warranted—version of "Gigli," a disastrous cinematic vehicle that goes so wrong in so many ways it ranks alongside 2009's Sandra Bullock-starring "All About Steve" in the annals of recent A-list blunders within the genre.

Zoe (Jennifer Lopez) is a pet shop owner—we know this because she is seen several times walking into a store called Hudson Mutts, not because she is ever actually captured doing her job onscreen—whose biological clock has long been ticking. She's a vision, no doubt about it, but can't find an upstanding man who is also ready to have a kid to save her life. On the very day that she is artificially inseminated, Zoe happens upon Stan (Alex O'Loughlin) after they hail the same cab and climb into the backseat together. It's an awkward first meeting, but there seems to be a spark between them. When he shows back up into her life soon after at a produce market, Zoe senses fate is telling her that there might be something special going on between them. The trouble now, however, is breaking the news to Stan that she is pregnant.

"You stupid-head!" Zoe name-calls Stan during their initial Meet Cute, symbolic of the level of wit and maturity "The Back-Up Plan" is playing on. Directed by Alan Poul and written by Kate Angelo, both with exclusive television backgrounds who may never get a second chance at features after this, the film exists in a vacuum where identifiable people who are living, or may have at one point lived, on planet earth do not exist. The characters are flimsy screenplay constructs used as puppets in what amounts to a woefully unfunny and charmless 105-minute sketch, each one more preening, over-caffeinated, and inhuman than the last. From Zoe's younger male friend Clive (Eric Christian Olsen), to her harried gal pal Mona (Michaela Watkins), to single mothers' support group leader Carol (Melissa McCarthy), to wisdom-spouting magical negro credited only as "Playground Dad" (Anthony Anderson), the viewer stares at these people and fails to find even a glimmer of authenticity in any of them. Casting the supporting roles with storefront mannequins or face-painted clowns would have achieved the same basic thing as these poor actors with no choice but to sink or chew the scenery.

As for the central focus—the romance between Zoe and Stan—it is so artificially orchestrated and empty-headed that it doesn't work for a second. Zoe and Stan are ciphers without any detectable interests, ideas or thoughts other than what is directly connected to the plot, their conversations with each other akin to the gibberish-speaking "Peanuts" teacher. Their interactions, from Zoe's mouth-agape response to seeing Stan shirtless on a tractor, causing her to drive into a tree, to their repetitive pattern of breaking up and getting back together, are reminiscent of grade-school behavior rather than the actions of adults well into their thirties. Upon finding out that Zoe is pregnant, it is understandable for Stan to have mixed feelings and cold feet, but the way misunderstandings and disagreements lead no less than three times to relationship fallouts is enough to wish they'd just remain apart and move on. Simply put, their romance is not, and never is, built on substance, but on what amounts to a plot gimmick and the necessities of hair-brained American rom-coms. Attempts at humor, by the way, fall into the slapstick variety and don't come close to eliciting chuckles of any size. In a sea of failed bits that don't properly mesh with the drama of Zoe's situation, the decided nadir is a water-birthing sequence culminating in animalistic roars from the mother-to-be followed by someone scooping fecal matter out of the kiddie pool she's sitting in. Yes, it's as bizarre and idiotic as it sounds.

Jennifer Lopez is sorely miscast as heroine Zoe, a woman whose quirks and cheery outlook on life leave her blissfully ignorant of the way people react to her sometimes oddball personality. For perhaps five minutes, this is actually an endearing quality. Then, alas, it is exposed as nothing more than a paper-thin, unconvincing affectation. The most fatal error in Zoe's writing is her lack of interest in children. For someone whose whole motive is to have a baby, it is never mentioned why she wants them so badly. As her pregnancy presses forward and her stomach balloons—leading to a scene where she splits a tight white dress down the backside, har har—she seems more interested in winning Stan's acceptance than anticipating and preparing for the baby she's gone to extra trouble to have. As Stan, Alex O'Loughlin (2009's "Whiteout") brings nothing special to the table. Through no fault of the actor's own, Stan is egregiously underwritten, bland, and disappears for stretches of time after he and Zoe get into one of their spats, no explanation given for where he's gone or what he's feeling.

As it must, "The Back-Up Plan" leads to mushy make-ups and a hospital labor scene so anticlimactic and ineffectual it is as if director Alan Poul must have thrown his hands up in defeat by that point and given up altogether. Zoe finally delivering her child and getting to meet him for the first time should have been afforded a little reverence, but it holds zero emotional value and the scene just abruptly ends. The outcome of her relationship with Stan is no less inconsequential, save for a final slap-in-the-face revelation that deems all that has come before as just about worthless. Then again, that's the ideal word to describe as a whole this painfully inept fiasco. Jennifer Lopez may not have been able to fulfill the promise she once held in her career thirteen years ago—you know, before she was nicknamed J. Lo—but she certainly deserves a whole lot better than the embarrassment found here.