The teen sex comedy, a dude-fest if there ever was one, gets a very overdue and very funny update in Kay Cannon’s “Blockers,” a gleeful, gross-out farce about the absurdities of gender bias.

Like “Porky’s” and “American Pie” before it, Cannon’s film begins with a sex pact. Three high-school friends are determined to lose their virginity on prom night before going off to college. The twist is that they aren’t an assortment of randy, pimpled guys. They’re a trio of curious, self-confident girls, already too wise to lose anything like their “innocence.”

The self-assured blonde beauty Julie (Kathryn Newton), daughter of the regretful single mom Lisa (Leslie Mann), makes plans with her steady boyfriend (Graham Phillips). The jock Kayla (Geraldine Viswanathan), whose father is the hulking but naive Mitchel (a terrific John Cena), impulsively picks a merry drug-dealing mate (Miles Robbins). And the bespectacled Sam (Gideon Adlon), whose father is the unhinged divorcee Hunter (Ike Barinholtz), thinks she’s attracted to another girl, but, as a trial, plans to sleep with her date (Jimmy Bellinger).

Each gets some decent moments, though the comic standout of the bunch is Viswanathan. Still, “Blockers” isn’t nearly as much about the kids as it is the parents.

When Lisa sees the girls’ pre-party texts on an open laptop, she deciphers the double-entendres of their emojis with the help of Hunter and Mitchel, and they embark on an outlandish quest to stymie their daughters’ “night of our lives” plans. What follows is a kind of prom-night odyssey through the awkward, much-feared sexual gulf between parents and their promiscuous young-adult kids.

But if any generation has any problems, it’s the older one. Hunter is a porn-addled social outcast after cheating on his ex-wife and Sam’s mother. Gary Cole and Gina Gershon make a hysterical cameo as kinky, over-sharing parents. The kids are all right; the parents are perverts.

Cannon, a former writer and producer of “30 Rock” and “Pitch Perfect,” makes a confident directorial debut. There are some lags in momentum and the centerpiece raunchy scene — seemingly a prerequisite to today’s comedies — comes off as a little formulaic. But the antic chemistry between Mann, Cena and Barinholtz is stellar. Together, they capture the panic, embarrassment and sentimentality of young-adult parenthood as they scramble after their kids, none of whom need saving.

“Blockers,” a Universal Pictures release, is rated R by the Motion Picture Association of America for “crude and sexual content, and language throughout, drug content, teen partying and some graphic nudity.” Running time: 102 minutes. Three stars out of four.

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Follow AP Film Writer Jake Coyle on Twitter at: https://twitter.com/jakecoyleAP

Jake Coyle, The Associated Press