YEARS from now, anthropologists tracking the development of Rogen Man may point to "Neighbors" as the moment he began to walk fully upright.

Seth Rogen has been his generation's icon of knuckle-dragging bachelorhood - imparting Falstaffian advice in "The 40 Year Old Virgin," fecklessly dating teens and smoking pot in "Pineapple Express," making tentative steps toward reform and domesticity in "Knocked Up," reverting to Hollywood hedonist in "This Is The End."

In "Neighbors" he takes the plunge, and we meet him fully submerged - married to Rose Byrne, living in a tidy suburb, cooing at his newborn, helping his wife pump breast milk, showing up for a job he doesn't really like.

It's a routine domestic life that he adores, and it's upended when the vacant house next door is sold to a college fraternity. Bongs and kegs and massive speakers are the first items out of the moving van.

"Neighbors" builds some shrewd comedy around the anxiety that many recently domesticated couples feel as freedom gives way to obligation - Rogen and Byrne strike a pose of exaggerated tolerance, attempting to meet the college kids (Zac Efron, Dave Franco) halfway, smoking a little, playing beer pong, signaling that they, too, are hip, or were very recently.

But life teaches us that there is no going back - you're either a parent or you're not, and soon the noise and selfishness of youth puts the fraternity in conflict with maternity/paternity - in "Neighbors," a slapstick (sometimes obscene) combat with no holds barred.

It's often funny. And well-cast. Byrne and Rogen have appealing chemistry and get help from Ike Barinholtz ("The Mindy Show") as a divorced pal, Lisa Kudrow as a put-upon university bureaucrat and Hannibal Buress ("Broad City") as a wifty cop.

I've sometimes been a bit hard on Efron - still traumatized by Nicole Kidman peeing on his face in "The Paperboy" - but he's good here in a role that has him embracing, rather than trying to edge away from, his Tiger Beat looks.

The movie gets sentimental as it asserts the primacy of hearth and home, but rights itself in the final moments in a chance meeting between Rogen and Efron in front of Abercrombie & Fitch, showing off six pack abs, and abs that come from too many six packs.