The first indication of a problem with this fourth in the series that began with the ground-breaking (and pastry-breaking) “American Pie” is that stars Jason Biggs and Seann William Scott are listed as co-producers.   Very few actors understand their characters well enough to avoid shifting them from what appeals to audiences to what appeals to the actors’ egos.

Take Stifler, for example.  One of the zestiest aspects of the first three films was this character, played by Scott.  He was the usual broad comedy figure of pure id, the literal spokesman for the hormonal longings of the four friends whose pledge to lose their virginity by graduation provided the storyline for the 1999 original.  But he served another function as well.  While our heroes were struggling with their romantic and sex lives, it was Stifler who bore the brunt of the most outrageous gags (in both senses of the word).  In order for the movies to work within their own construct, it is important for the other characters and the audience to like Stifler enough for him to be an instigator (urging the other guys on, throwing wild parties) but not enough for us to feel that it is unjust or wrong when awful things happen to him.  Now, presumably at the instigation of producer Scott, Stifler does not suffer any comic consequences and by the end of the film is supposed to be sort of likeable.  That is one of several things this movie gets wrong.

“American Pie” was a comedy about four teenage boys who were desperate to have sex partly because they were teenage boys and partly because of their pride — they were spurred on by a classmate who claimed to have had sex and they did not want him to be ahead of them.  Jim (Jason Biggs) was the character whose role has been endless excruciating humiliation — in the film not only did his father offer sincere but painfully boundary-intruding advice but his extremely embarrassing attempt at having sex with a pretty exchange student was broadcast on the then-novel internet.  Oz (rangy Chris Klein) and Kevin (doe-eyed Thomas Ian Nicholas) had some relationship problems to sort out and Finch (ethereal Eddie Kaye Thomas) was looking for something a little different.  What made the film so revolutionary was in part how explicit and raunchy the humor was but more the portrayal of the girls in the film as sexually confident and as people, not just objects to inspire lust and fear.

Teen sex comedies are fun because that stage of life is so sharply exaggerated.  All of the usual adult concerns about sex and love seem insurmountably (so to speak) perplexing and more dire when you are experiencing them for the first time and seeing our worst fears realized on screen is cathartic, reassuring, and funny.  But they are in their 30′s now, and that is different.

The movie opens with a bouncing, squeaking bed and a song from R. Kelly.   Jim and his “This one time? At band camp?” wife Michelle (Alyson Hannigan) are indeed in bed, but he is on his laptop and she is rocking their 2-year-old.  Yes, just like teenagers, parents are also sex-deprived.  But as we learned in “Hall Pass” and “The Change-Up,” that does not make it funny.

Everyone comes back home to Michigan for their 13th high school reunion.   Why the 13th?  They sort of spaced on the 10th, or, in other words, three years ago the cast members still thought they had other options.

It begins as Jim, once again, has a painful experience when his attempt at a solo sex act is interrupted.  This time, instead of his father, it is his toddler.  He smashes a sensitive part of his body in the laptop and goes to the bathroom to get a band-aid only to find Michelle in the bathtub, also enjoying a solo sex act.  Embarrassment all around.   Jim’s squashed sensitive part will be on display shortly, when he finds himself half-naked in the kitchen and tries to cover himself with what turns out to be a glass lid.   He will also have to deliver a drunk, naked 18-year-old to her bed without her parents or Michelle seeing them.  And he will appear in front of a large group of people in bondage gear that looks like goth lederhosen.  Meanwhile Oz and Kevin meet up with their high school loves (Tara Reid and Mena Suvari), making them re-think their current relationships.  And Finch arrives on a snazzy motorcycle with tales of exotic adventures that have everyone else feeling envious about the lack of adventure in their lives.

Fun!  Not.  ”Am I wrong or was this place a lot more fun when we were younger?” a character asks.  He’s not wrong.  It is hard to say what is weaker, contemporary references like Kathy Lee and Hoda, Mario Lopez, JDate and reality TV dance competitions or attempts at humor that are merely references to the previous films or other 90′s markers.  If the menton of Chumbawumba or a cameo by one of the minor performers from the first film seems hilarious to you, no, you’re still better off re-watching the original.

The 30-comethings are out-classed by returning older generation (and fellow Christopher Guest ensemble stars) Eugene Levy as Jim’s widowed father and Jennifer Coolidge as Stifler’s mom.   “When are you going to realize that things are never going to be the way they used to be?” Jim asks.  Exactly.

Parents should know that this film has constant very crude and raunchy sexual references and situations and very explicit language, nudity including full frontal male nudity, pornography, drinking and drug use by teenagers and adults, and brief scuffles.

Family discussion:  Which character changed the most since the first film in the series?  Why was it so difficult for the characters to talk to each other about their feelings?

If you like this, try: the first three in the series

NOTE:  This review reflects an incomplete viewing of the film as there was a problem with one of the audio tracks at the critics’ screening.  While it is unlikely that seeing it with the full musical track would substantially change my assessment of the film, I am certain that seeing it as intended would have significantly improved the pacing and tone.