Chick lit is growing up. In 1998 a wise-cracking, boy-crazy British career girl named Bridget Jones took publishing by storm and spawned dozens of imitators. Now a new breed of fictional heroine is bringing Bridget’s wry humor and brutal candor not to dating but to motherhood; publishers call the new genre “mommy lit.” So far this summer, “Babyville,” Danielle Crittenden’s “Amanda Bright@Home” and Adele Parks’s “Larger Than Life” have hit bookstores with the same candy-colored covers as their chick-lit cousins. But unlike their childless sisters, these heroines would pass up a Prada bag for a good night’s sleep and the patience to sing yet another round of “Itsy Bitsy Spider.” Women have always written about families, of course, but this new crop of books takes an unflinching look at the ambivalence that goes along with motherhood while still appealing to a mass audience. “Readers today know being a mom is complicated,” says Deborah Birkett, who runs the three-year-old Web site Chicklit.com. “They want to read something about it that isn’t pulp romance but also isn’t ‘The Bell Jar’.”

For publishers, the evolution from dating tales to domestic travails is only natural. After the success of Helen Fielding’s book, Simon & Schuster, Kensington, Avon and Harlequin launched chick-lit imprints of their own. Last year fictional heroine Kate Reddy became a touchstone for weary working moms struggling to have it all. When “I Don’t Know How She Does It” lingered on The New York Times best-seller list for 11 weeks, other publishers took note. “We realized that our audience was maturing,” says Louise Burke, who heads S&S’s nine-month-old chick-lit imprint, Downtown Press.

With nearly a dozen more mommy-lit books on the way, publishers clearly think they’ve found a bright light in an otherwise grim sales season. Across the board, hardcover sales are in a double-digit slump and paperback sales are flat. But Bridget Mason, a fiction buyer for Borders, says that mommy lit is selling well. “Once the genre gets more established,” says Mason, “we think it will be huge.”

Readers accustomed to happy endings may find the unvarnished view of modern motherhood a bit unsettling. Just like in life, the fictional births are often followed by prolonged depressions, and the stresses of child rearing can bring shaky marriages to an end. “Babyville” author Green says honesty is important as long as her plots remain “escapist and entertaining.” Other writers are more ambitious. In her seventh novel, “We Need to Talk About Kevin,” author Lionel Shriver details every mother’s nightmare: her protagonist’s firstborn turns out to be a Columbine-style killer. The book has won raves from critics who’ve called it “psychologically astute.” Others have hailed it as an underground feminist hit.

Mommy-lit publishers say they’re gearing up to lead female readers through divorce, menopause and the empty nest. Next year Downtown Press is bringing out a book about four disgruntled middle-aged marrieds called “Babes in Captivity.” But the publisher is also hoping to reinvigorate the old chick-lit formula–this time with a big dose of testosterone. Next summer they’ll begin publishing novels about ambitious young men searching for Ms. Right. The name of this new line? They’re calling it “lad lit.”