It's Complicated is a middle-aged sex comedy but with more rom-com urges than farcical ones. It's from writer-director Nancy Meyers, who has found a comfort zone in gentle, even warm comedies about older adults facing complications that re-direct their lives into pleasantly unexpected emotional channels. Complicated forges ahead with these themes. Because no one else in Hollywood seemingly makes movies for middle-aged moviegoers, especially women, Meyers inevitably scores box-office successes, and this one should forge ahead in that area, too. Universal releases the film Christmas Day.

What Meyers doesn't do is take chances. She sticks to formula and predictability. In Complicated, this is as much a matter of casting as writing.

Meryl Streep, apparently not wasting any cooking lessons she had for Julie & Julia, plays a divorced owner/pastry chef of a successful Santa Barbara bakery/restaurant. She is only now coming to terms with her divorce from Alec Baldwin, who dumped her 10 years earlier for a much younger woman. Even so, shopping for plastic surgery and building an extension to her rustic house indicate a certain restlessness despite her apparent equanimity.

The graduation of one of their three grown children on the East Coast throws her together with her ex at a time when his wife (Lake Bell) isn't around. Wine flows, sparks fly and -- you would never guess, but then again, you probably will -- the two launch an unplanned, drunken affair. Suddenly, Streep is the other woman.

But the casting foreshadows most of the dramatic turns. Baldwin has developed a second career in films and television by more or less spoofing his macho image. So his character, a comic exaggeration of male befuddlement with womankind, is never a credible life choice for the restaurateur. Then, too, Steve Martin has just walked in: He's the architect who is going to change her life with that home extension, and you know, even though he's more subdued than you might expect, that he isn't in the story to discuss the importance of retaining walls.

In the movie comedy world dominated by Judd Apatow, Meyer's idea of naughtiness is charmingly quaint. The older adults -- hide this from the kids -- smoke pot! Yes, they do. Streep drops her bathrobe to expose her over-50-year-old body just as Diane Keaton did in Meyers' Something's Gotta Give. (No, of course you don't see anything.) The film's really racy moment comes when Baldwin's private parts are accidentally Skyped to an unwilling viewer.

The near-farcical maneuvers by the parents in and around their kids (Caitlin Fitzgerald, Zoe Kazan and Hunter Parrish) and one prospective son-in-law (John Krasinski) and the shocked/delighted reactions to the affair by her gal pals (Rita Wilson, Mary Kay Place, Alexandra Wentworth, Nora Dunn) get milked for all possible laughs they will yield.

What Meyers has going for her in all the films she has directed from her scripts is her ability to evoke a fantasy world where grown men can cry and realize their mistakes while grown women love them for that. Cynicism -- real cynicism, not the catty, superficial kind espoused by this First Wives Club chorus -- is banished, and true love still is a possibility.

To whatever degree the writer-director is rewriting her own life story, crucially she is doing so for countless middle-aged women, and probably more than a few guys who need to swallow all the pills Baldwin's character does to get through the day.

This is a comfort zone for such viewers even if the characters are no more real than the models in Vanity Fair ads. Streep is a vision of mature loveliness, a smart, sexy mom who always knows the right things to say to the kids and how to extricate herself from embarrassing situations. Far from the real world, she lives in a multimillion-dollar home, can -- after a suitable number of comic mishaps -- make sense of her life and even get Skype to work without having to consult younger family members.