THE WORLD KNOWS that Jamie Lynn Spears has turned up 16 and pregnant. What makes this newsworthy is that she starred as the nice girl on Zoey 101, a Nickelodeon show aimed at “tweens” ages 9 to 14. Jamie Lynn was supposed to be the smart, sensible alternative to her older sister, Britney Spears. She was “the good one.”

The children’s TV network may squeeze this lemon of a situation into the lemonade of a “teachable moment.” It’s hoping that the Jamie Lynn story will spawn serious conversation between parents and their young daughters.

I hope the girls explain it to Mom and Dad.

What the parents need to learn is that you don’t buy anything from the Spears celebrity store and expect a wholesome message to emerge. The turnip trucks must be getting great mileage these days because so many parents have apparently fallen off them.

Of course, Zoey 101 was never about Jamie Lynn. Thousands of young actresses would have happily played Zoey, but the one the producers chose was Britney’s sister. And so the sizzle in the program was not that Jamie Lynn was a good seed, but that she came out of the same packet as her bad sister. It was always about Britney, and the parents didn’t get it.

In olden days, companies used to advertise themselves as a “brand you can trust,” especially when selling products for children. They defended their reputation. The Spears organization, run by mother Lynne Spears, knows it, too, has a reputation to protect, a reputation for churning out bad girls, or more precisely, good girls turned bad.

Parents didn’t get that, either. As an erotic theme, the despoiling of innocence is older than the Romans. Lynne Spears is a proven expert on serving up her young daughters.

The trajectory goes as follows: At age 11, Britney displays her purity on The New Mickey Mouse Club. She quickly grows into a tarty teen star, but vows to “remain a virgin until marriage.” Meanwhile, on a stage populated with big teddy bears, she performs a bump, grind and moan routine, plus some pole dancing. Clueless mothers take their 7-year-olds to see it.

By 20, Britney appears on the cover of a Mexican men’s magazine with “Sexperto” written in big red letters over her privates. By her mid-20s, she’s been through drug rehab, losing custody of her children, hit-and-run-driving charges, and a couple of failed marriages, among other events.

It’s now Jamie Lynn’s turn at bat. She established her virginal bona fides in Zoey 101. Then she’s turned 16, time for her high dive from chastity into the pits of sexual availability. Mom could have insisted she use birth control. She could have helped Jamie Lynn quietly end the pregnancy. But the business model requires a drawn-out public decline.

People who didn’t even know that Britney had a little sister now know her name and that’s she’s been, as they say, knocked up. And had she not convincingly posed as the good one, her turning bad would be far less interesting. We read that Mom sold the pregnancy story to OK! magazine. Jamie Lynn is launched.

Nickelodeon appears uninterested in pulling the fourth season of Zoey 101, which debuts next month. However, the network may do a special linked to the Jamie Lynn situation designed to teach her young fans about sex and love.

Many parents would no doubt see such a program as educational, rather than as a means to keep everyone engaged in the sordid Spears family drama (off which Nickelodeon profits). Perhaps their daughters can draw a diagram of how this all works.

Froma Harrop is a member of The Journal’s editorial board and a syndicated columnist.