Sensing a fertile market, no fewer than five shows are competing for parents’ attention (and Pampers ads) on the cable dial. Each reaches more than 50 million households and all have two things in common: loads of adorably telegenic small persons and lots of baby-friendly, gender-neutral, eco-correct enlightenment. But there are differences, too. Each half-hour series stakes out its own age-related turf, from prenatal care to the preschool blues. As for the hosts, not even Johnny, Oprah and Dr. Joyce project a broader range of personae.

Video parenting’s oldest and most venerated practitioner is Dr. T. Berry Brazelton, whose “What Every Baby Knows” has been airing on the Lifetime channel for eight years. This season the 74-year-old pediatrician took his show on the road, visiting families from Boston to the Alaskan boonies to observe how America is raising its young.

Brazelton specializes in folksy reassurance. When a poor Texas farmwife confides her guilt about not bringing home a second paycheck, Brazelton nods toward her glowing children, crinkles his eyes and says: “You’re doing a lot you’re unaware of.” Then he’s off to consult with a Hispanic couple puzzled by their young son’s failure to learn English in school. After discovering that the father prefers to speak Spanish around the house despite the fact that his English is almost flawless, Brazelton gently scolds him, then delivers an illuminating analysis of language problems among bicultural children. Though Brazelton knows it all-he’s written 23 books on child development-he always exhibits a touching respect for what parents have to say. He’s Wilford Brimley with an M.D., and his show is the cream of its class.

TV’s newest parental survival guide is Penelope Leach, the British-born host of Lifetime’s “Your Baby and Child.” A child psychologist and mother of two, Leach turns over each episode to a single problem: dealing with temper tantrums, perhaps, or getting a toddler to sleep through the night. Then, sort of like Oprah, she fields questions from a studio audience of parents and children.

With her patrician overbite and chirpy exuberance, Leach comes on like a candidate for the Royal Shakespeare Company. She e-n-u-n-c-i-a-t-e-s. She rolls her eyes, works her brows and flails her hands. She periodically exclaims, “Oh, boy!” She’s also eminently sensible. When a mother complains that her 3-year-old constantly demands snacks, Leach responds: “Your child won’t starve [eye roll] if he doesn’t get what he fancies today, because what he fancies today [grimace] i’s the opposite of yesterday [jab of thumb over shoulder]. Truly he won’t!” Nor will your attention ever wander when this woman is doing her act.

“American Baby,” airing on the Family Channel, concentrates primarily on the first year of life. Judy Nolte, editor of American Baby magazine, presides with crisp, no-nonsense efficiency. But this show is mostly talking heads, and the talk can get awfully technical. In a segment on prenatal testing, graphically illustrated with shots of a needle being jabbed into a pregnant abdomen, a pediatrician explained the intricacies of “Chorionic Villus Sampling” and the “Maternal Serum Alpha Fetoprotein Test.” Informative, yes, but no attempt was made to lay out the risks of such tests-or describe who’s a good candidate for them and who isn’t. Nor does Nolte discourage her guests from hawking their wares. One child psychiatrist plugged both his latest book and his new day-care program. Most unsettling moment: during a discourse about what the young can do for conservation, the editor of P-3 magazine (“The earth-based magazine for kids”) suggested that children “time their parents’ showers.” Yikes!

Jane and Katie, watch out. Not only does Leeza Gibbons host Lifetime’s “Growing Up Together,” but she’s an on-camera reporter for “Entertainment Tonight” and the mother of both a toddler and a new baby.

A classic Type A-plus, Gibbons loves taking viewers out of the studio. She’s visited a business office to chat with working moms and their bosses, toured a hospital nursery with some expectant mothers and dropped by a day-care center to ask all the questions potential customers would ask. The woman gets around, but she can also get on one’s nerves. With her Hollywood-wife blond mane and glitzy jewelry, Gibbons’ looks like she just lunched at Spago. She also tends to lay on the gush. Following a nature walk: “We learned to be open to our senses. We learned to allow nature into our lives. It was really neat!” But just when you’ve really had it, Gibbons visits a preschool for handicapped children and cuts to your heart. Playing with a toddler with cerebral palsy, she was warm, natural and instructive. Kind of neat, actually.

First there’s the sitcom-bouncy theme song (“Healthy kids are haaaaappy kids . . .”). Then on strides the star-gorgeous fashion model Kim Alexis. What’s next, a laugh track? In fact, the Family channel’s “Healthy Kids,” the only one of the five series approved by the American Academy of Pediatrics, confronts some of parenthood’s heaviest concerns (even though it’s targeted at kids under 4). Such as: talking to children about AIDS, helping them cope with the shock of divorce, raising them prejudice-free even teaching them about the dangers of handguns.

Though Alexis, an engagingly earnest mother of two, consults lots of experts, the show’s true stars are other parents. During a segment about “words that hurt” (e.g. “I wish you were never born”), mothers and fathers poignantly recall the lifelong emotional wounds inflicted on them by their own quick-to-cut parents. “I was told I was clumsy as a child and it became a self-fulfilling prophecy,” says one mom. Later, discussing “children and grief,” a young father reports that his 2-year-old started having more “potty accidents” after learning his grandfather had died. Such regression, he’s quickly assured, is a common-and temporary-reaction. Even Kim looks relieved.

How does video parenting rate among the pediatric old guard? Let’s beam up Dr. Spock himself. “The most beneficial aspect of such shows is having the parents on,” said the 89-year-old Spock from his retirement home in the Caribbean last week. “It’s very valuable for parents to hear the experiences and opinions of other parents. Americans are far too respectful of child-rearing professionals.” As for the pros who are moonlighting as TV hosts, Spock cautioned: “If they’re pompous, condescending or overly authoritarian, they could do harm by making parents lose faith in their own instincts.” No one ever accused him of that, which raises a final question: would Spock have liked to do television, too? “Sure,” he chuckled. “I wouldn’t have minded at all.”

Sounds like someone forgot to call The Doctor.