"The Change-Up" is a body switch comedy. For anyone, say, 30 years of age or older, that statement alone might be enough to make you stay away.

We have seen this scenario played out so many times and rarely does it actually work.

All mainstream studios, everywhere on this planet, recycle ideas. Producers want to be reasonably sure they'll get a return on their investment, so they fall back on tried-and-true genres and sub-genres. It's a cinematic fact of life.

But this particular sub-genre is so narrow, offering such a finite number of possibilities, that it was pretty much exhausted after a few films. I just cannot believe Hollywood is still making this movie.

The earliest body switch comedy I can dig up is Hal Roach's 1940 "Turnabout," and it's illustrative to compare "The Change-Up" to that film.

In "Turnabout," a chauvinistic husband and his pregnant wife argue in front of a Buddha statue and somehow swap bodies. They live each other's lives for a while and inevitably come to a better understanding of each other. The concept was quite predictable even in 1940, but as he always did, Roach mined it for a bunch of clever sight gags and witty lines.

In "The Change-Up," best friends Mitch (Ryan Reynolds) and Dave (Jason Bateman) go out drinking, then urinate into a public fountain (also adorned with a statue) and wake up in each other's bodies the next morning.

Dave is a lawyer trying to make partner, he is married to Jamie (Leslie Mann), and has three children. His life is perfect on the surface, but he is a workaholic whose marriage is in a rut because raising children takes so much time. Boo hoo. Dave and Jamie are obviously making six figures, so they have all sorts of options to give themselves some free time.

Mitch is a loser, plain and simple. He is a failed actor who spends most of his time stoned, playing with a sword and saying the most inappropriate thing he can think of.

The movie introduces Mitch as a playboy, but he is actually a predator. He has a Tuesday night romp with a woman named Tatiana (Mircea Monroe) each week, and it turns out Mitch cruised single-mom Lamaze classes to find Tatiana, who is eight months pregnant.

Frankly, I disliked both characters so much I didn't care how the movie developed them. Not that the characters were actually developed, mind you.

The few body switch comedies that work ("All of Me" and "Freaky Friday" come to mind) have fun forcing each actor to take on the mannerisms of the other. But Bateman's career is based on his understated straight man persona, while the only thing Reynolds has going for him is good looks.

Given so little to work with, neither actor makes an attempt to "play" the other. That, or they did it so badly I didn't even notice.

"The Change-Up" was filmed and is set in Atlanta, so I wish I could support it.

But the only thing that sets "The Change-Up" apart from other body switch comedies is the depth of its depravity. This movie repeatedly, relentlessly sets up jokes then goes for the grossest punchline imaginable.

The very first word of dialogue in this movie is the "f-word," which is appropriate because we hear it incessantly. Quentin Tarantino's work seems chaste by comparison.

The first sight gag involves a diaper change gone wrong. Dave must change the twins in the middle of the night. One of the babies is on the changing table. Dave removes the old diaper. The clean diapers have fallen on the floor, so Dave squats to pick one up. While he is crouched down, what should have gone into the diaper instead squirts not only on Dave's face, but directly into his mouth.

Believe it or not, this movie sinks lower and lower after that.

Jeff Marker is a media studies professor at Gainesville State College.