Raunch isn’t selling like it once did.

“Ted 2” is the latest bawdy comedy to struggle at the box office, opening to just $32.9 million this weekend, exposing some kinks in the R-rated comedy genre’s armor. The disappointing returns come on the heels of “Spy’s” underwhelming $29.1 million debut earlier this month. Neither film is a box office disaster — “Spy” stands to be profitable, and foreign grosses should push “Ted 2” into the black — but they are not the ticket selling phenomenons many analysts expected they would become.

“Entourage” also carried an R rating, and bombed with a dismal $39.7 million in receipts. It’s unlikely that any MPAA designation could have saved that moldy bro-mance. Its failure is attributable to its origins as a bigscreen version of a television series that is several seasons removed from the zeitgeist.

The difficulty is that unlike other genres, novelty is a key selling point for comedies. That makes them unusually execution dependent.

“When a comedy is a sensation, it’s normally a picture that no one saw coming,” said Paul Dergarabedian, senior media analyst with Rentrak. “R-rated, raunchy comedies are one of the few areas where originality is king.”

In the past, a R rating was seen as an essential ingredient to a comedy’s success. Envelopes had to be pushed to the bleeding edge, sacred cows needed to be eviscerated, in order to differentiate bigscreen comedies from edgier television fare, or so the thinking went. In previous summers, profits followed this willingness to expand the boundaries of what was appropriate fodder for jokes (Try not to avert your eyes as Rose Byrne breastfeeds Seth Rogen in “Neighbors”! Get gleefully repulsed while Maya Rudolph defecates in the street in “Bridesmaids”! What debauchery will the “Hangover” wolf pack get into next?).

Frontal nudity abounded and blue language became positively ultraviolet as comedies engaged in a dizzying game of one-upmanship. It helped that unlike superhero movies, which carry pricetags north of $100 million, these films are a cost-effective bunch, rarely setting studios back more than $60 million.

Last summer the likes of “Neighbors,” “22 Jump Street,” “Let’s Be Cops” and “Tammy” all mixed laughs, filth, four-letter words and a R rating to healthy box office returns. But the teflon genre may be showing signs of wear and tear. After all, the best performing comedy this year, “Pitch Perfect 2,” racked up $276.8 million globally by appealing to younger female moviegoers. A PG-13 rating was a major factor in the picture’s success, making it more palatable for families and broadening the film’s appeal.

It’s hard to know why “Spy” and “Ted 2” were such slow starters. It’s not clear that quality was a factor. While “Ted 2’s” reviews were middling, “Spy” was rapturously received. In fact, “Spy” has shown some impressive staying power, falling by slender percentages in subsequent weeks, which signals that word of mouth is strong.

In the case of “Ted 2,” some pundits argue that the picture was overly familiar. The posters and television spots were too reminiscent of the promotional campaign for the first “Ted,” robbing the picture of the freshness needed to build buzz.

“The novelty wore off,” said Jeff Bock, a box office analyst with Exhibitor Relations. “They didn’t up the ante enough to create another must-see film.”

Now all eyes turn to “Trainwreck,” the buzzy Judd Apatow and Amy Schumer pairing that bows July 17, and “Vacation,” a July 29 reboot of “National Lampoon’s Vacation” that weaves rim job jokes and visual gags about Chris Hemsworth’s Norse God-like manhood into the Griswold family saga.

Phil Contrino, chief analyst and vice president of BoxOffice.com, thinks both of those films will resonate with audiences, obviating any concerns about the health of the genre. Scheduling, not rating, is responsible for the dispiriting returns, he argues. “Spy” got dinged by blockbusters like “Avengers: Age of Ultron,” while “Ted 2” received a shellacking from the twin superpowers that are “Jurassic World” and “Inside Out.”

“Comedies that try to open a little earlier in the summer tend not to perform as well,” said Contrino. “August and late July seem to be the right period of time for these kind of films. People have blockbuster fatigue by then and they’re sick of watching things blow up.”