Kids grow up so fast these days, and that's not a commentary on the wise-beyond-their-years, smart-alecky younger set in "Melissa & Joey" -- though there are two such children in this utterly conventional in its unconventionality ABC Family sitcom.

It's actually referring to the fact that Sabrina, the Teenage Witch and Blossom's mop-haired buddy are now sharing their own sitcom home. (This is their second pairing; in 2009, the two drew good ratings in the ABC Family film "My Fake Fiance.")

Melissa Joan Hart's Mel Burke is a city councilwoman in cleavage, short dresses and spiked heels -- the better to pratfall with, my dear -- and is faced with a dilemma: Her brother and his wife are locked up for theft, and she's really not ready to properly parent their two adolescent children, Ryder and Lennox. Mel can hardly keep her constituents happy: They're tossing trash on her front porch to protest reduced pickup dates.

Then, like a strange Mary Poppins, Joe Longo (Joey Lawrence) literally walks into her home. He's a commodities trader who lost job, home, car and wife thanks to Mel's relatives' shady dealings. In no time, he has volunteered for the nanny job and even references "Charles in Charge." Let the sexual tension and inverted gender role jokes begin!

Lawrence is the stronger comic presence here; despite his beefed-up arms and shaven head, he's got a twinkle in his eye. He's a relief to Hart's dithery indecisiveness, which doesn't seem real for an instant. Unfortunately, they're both weighted with cringe-worthy lines: "Did your hair get sick of you and leave?" she asks him; he wonders if only "Vagino-Americans" can apply for the nanny job.

They're not alone in silly attempts at "edginess." When Ryder asks Mel's assistant, Rhonda, for basketball tips, she tells him snidely, "We Asian women are all about the Hoops."

It's a shame that "Melissa & Joey" isn't more about the laughs. It's far from unwatchable, and there's potential in its leads, if they're left to their own devices. It's also possible that this middle-of-the-road sitcom will hit nostalgic buttons in former "Sabrina" and "Blossom" fans. In the end, it's nice that Lawrence and Hart are getting work. On the other hand, the work ain't anything special. Whoa, indeed.

Airdate: 8-8:30 Tuesday, Aug. 17 (ABC Family)
Production: Hartbreak Films, ABC Family
Cast: Melissa Joan Hart, Joey Lawrence, Taylor Spreitler, Nick Robinson
Executive producers: Paula Hart, Bob Young, David Kendall, Melissa Joan Hart, Joey Lawrence, John Ziffren
Creators-writers: Bob Young, David Kendall
Producer: Ken Ornstein
Director: Ted Wass
Director of photography: Jim Roberson
Production designer: Scott Heineman
Costume designer: Elizabeth Bass-Galespie
Casting: Greg Orson, Lesli Gelles