‘The Change-Up': A Sex Comedy That Hates Sex

Who needs a production code when studio movies about the humpty-hump have all the bravado and recklessness of your maiden aunt Gertrude?

Why do so many Hollywood sex comedies hate sex so much?

This year alone, we’ve already had “No Strings Attached,” “Friends with Benefits” and “Hall Pass,” three movies that overtly state that all carnal relations between two consenting adults are icky and soul-crushing if they take place outside of the blessed state of matrimony, or at least couplehood.

These movies entice audiences with storylines that promise to be about freewheeling, mature sex unencumbered by guilt or convention, but by the final reel, you can pretty much bet the farm that a ring’s going on someone’s finger or that chastened spouses will learn their lessons.

Who needs a production code when studio movies about the humpty-hump have all the bravado and recklessness of your maiden aunt Gertrude?

The latest of these morality plays, “The Change-Up,” starts out with a hard-R “Freaky Friday” premise — button-down dad and lawyer Jason Bateman changes bodies with irresponsible chick magnet Ryan Reynolds — and pretty much sucks all the potential fun out of it as quickly as possible.

Bateman’s Dave has worked his way up from poverty, but even though he’s got the house, three kids, and hot wife Jamie (Leslie Mann), as well as a law partnership within reach, he can’t turn off his work ethic long enough to enjoy life or even give Jamie an hour a week devoted to actual conversation.

Meanwhile, Dave’s lifelong best bud Mitch (Reynolds) lives like a frat boy, struggles to get acting gigs, and purports to have an endless stream of babes coming in and out of his apartment.

One drunken night, the two urinate into a fountain and simultaneously wish for each other’s lives, and wouldn’t you know it, the next morning they’ve gone all “Like Father, Like Son” or “Vice Versa” or “Dream a Little Dream” or whichever is your favorite body-switching movie. And then…

Well, not much, actually. Mitch learns the usual lessons about familial responsibilities and opening himself up to love, although the movie miraculously teaches him how to be a really good lawyer as well, suddenly taking over Dave’s complicated merger deal with no legal training outside of some “Law & Order” reruns.

Dave, meanwhile, having endured long periods of marital bed-death, looks forward to the idea of responsibility-free sex, but winds up choking once he realizes that he and Mitch have very different taste in women. (Suffice it to say that Mitch trawls Lamaze classes for single mothers.)

The script, by Jon Lucas and Scott Moore (“The Hangover”) is a mess — it strives to juggle bawdy smuttiness with violin-section sentimentality, resulting in unfunny incoherence. (Poor Leslie Mann gives a genuinely heartfelt and witty performance as a woman desperate to regain her husband’s attention, but it feels beamed in from an entirely different movie.)

Worse still, the writers can’t even get their body-switching mechanics right: Dave and Mitch have the requisite scene where they try to explain to Jamie what’s happened to them, but since Dave bobbles her questions about their anniversary and Jamie’s favorite color, she’s not buying it.

This conversation then apparently completely flies out of her mind, because hours later, Mitch-as-Dave can’t remember their nightly dinner song and he mispronounces their daughter’s name, and Jamie just gets mildly peeved. Shouldn’t she at least accuse him of trying to maintain the charade that bodies have been switched?

There’s also at least some degree of misogyny at play in “The Change-Up” — Olivia Wilde is the only actress here who gets to disrobe without being humiliated; otherwise we get Mann taking a violent bowel movement, a topless pregnant woman whose baby’s kicks are visible through her stomach, and an over-the-hill porn actress whose surgeried visage and ridiculously artificial breasts are played for laughs.

Bateman and Reynolds do what they can with the material, but since both actors possess such a dry, deadpan comedic style, the prospect of them playing each other doesn’t yield the comic possibilities of one of them trading places with, say, Will Ferrell.

Bateman seems to be having fun with the kind of crass, potty-mouthed character that doesn’t usually come his way, and he makes the most of the physical-comedy moments involved with Mitch-as-Dave trying to figure out how to feed and diaper two yowling twin babies.

“The Change-Up,” like so many American movies, feels like the product of sex-phobic 12-year-old boys whose response to the big, bad world is to run back to mommy’s leg. And if the movie were about that panic, it’d be one thing, but instead it’s the never-addressed elephant in the room — or rather, the bra and panties on the bed that get picked up, giggled over and then flushed down the toilet.