Alisha Richardson is 18 years old and just left for college last week. Like most college students, she believes she has a constitutional right to have a cellphone connected to her body at all times of the day.

Which is not to say that her younger sister, Alexandra -- "who is only, like, 12 or 13 or something" -- needs to be in touch with her friends 24/7.

"Like yesterday, we were at the mall, and she got about eight phone calls in two hours. Her friends were calling about going to a movie; a guy asked her to come to the pool. . . .

"And THEN, get this, we had to buy her a second phone not long after she got the first one because she broke her first phone playing tag!"

Is Alexandra too young to have a cellphone, as her older sister believes? Or, in this post-9/11 age, isn't it necessary for parents to have an electronic leash tethered to their "tween-age" youth?

As usual, big business is way beyond debating the pros and cons of elementary and middle schoolers tucking cellphones into their backpacks. Ten- to 14-year-olds are the fastest growing segment of cellphone users.

Mattel is introducing a My Scene Barbie cellphone, Disney and Sprint are partnering to launch a wireless phone service for kids, and Target is selling cellphones that glow in the dark.

Decorative face plates of the kind the Richardson girls and their mom bought to distinguish their phones are red-hot, as are phones like the Motorola 710, with which you can take pictures, record audio and video, play video games, e-mail and text-message your friends AND listen to your favorite music via mp3.

That's what Danville entrepreneur Charles Fulp carries. He's the co-owner of One-Stop Cellular, and he's heard all about the prediction that child cellphone users will grow by 22 percent next year.

From his perspective, if you're a parent, here's how the hard sell typically works:

First, it's: But Mom, Daniel got a cellphone.

Then, a week later, it's: And now Taylor has one, too!

Throw in one well-timed bicycle accident -- "I was on the other side of [insert busy thoroughfare here], and I had no way to get in touch with you!" -- and before long you'll find yourself in one of Fulp's 55 stores, inquiring about the "family plan."

"Once one kid in a group gets one, everyone in the group's going to get one," he said.

Other weapons in the kid-cell arsenal include:

n "How will you know what time to pick me up after soccer practice/Odyssey of the Mind/school field trips unless I call and tell you?"

n "You'll always know how to find me when I'm at the mall or out riding my bike."

n "I keep having to borrow my friends' minutes on their phones, and that's not fair."

n "For the first time, I'm having to walk to and from school alone. Aren'tcha worried?"

Melissa Friedman of Roanoke found herself under attack by her 13-year-old, Amy, whose two older sibs already had cellphones. She resisted Amy's pleadings for more than a year until security concerns finally pushed her over the edge.

Convenience is a factor, too, especially when she's late leaving work -- and the family's land line is busy.

"I think especially for Amy, it was the wanting-to-be-a-grownup thing," she added. "Having your own phone is sort of like getting to wear makeup."

Amy's dad, Frank, a lawyer, was a tougher sell. So Amy sent in the big guns. She got her mom, who is also a lawyer, to ask the probing question: "What is the value to you if your daughter is stranded somewhere and needs to get in touch with you?"

Dad finally conceded, "Obviously, it's priceless."

While her parents pay the monthly family-plan bill, Amy pays for text-messaging and any minutes she uses above and beyond the plan.

Though many schools banned cellphones pre-9/11, most now allow them with the provision that they stay turned off during class.

"You'll see a lot of students checking their messages between classes, but they're not supposed to be talking on the phones in school," explained Allen Journell, Roanoke County's assistant superintendent of administration.

"We do go through problems every year at the start of school. The students are used to them being on 24/7, and they're reluctant to turn them off at first."

Roanoke County uses a two-strikes-and-you're-out policy. If students use their phones in class after they've already been warned against it, the phones are confiscated -- and only parents can get them back.

Roanoke City Schools has a similar phones-off policy, as do other school districts in the region. "We've had parents say they need to be able to reach out to the students instantly, but we have to protect the instructional process in our classrooms," said Sharon E. Richardson, executive director for student services.

Besides, there's always another way to reach your kid should an emergency arise: the school office land line, which is still answered -- usually -- by an actual human being.