Once upon a time, girls wrote their secrets in diaries and locked them with flimsy gold-tone keys to keep out prying brothers. Once, they twisted apple stems, one twist per letter of the alphabet until the stem fell off, to discover the initials of the man they would marry. Once girls even sent each other notes on scraps of paper, and were then sent off to the principal's office for doing it.

No more. Or, that is, no more if various electronics manufacturers have their way. Forget apple stems and scraps of paper. Childhood has gone digital.

Video games have been around for years, but with every new toy season, more and more childhood activities go electronic. Now, with Casio's "My Magic Diary" and Tiger's "Dear Diary ...," kids can write brief entries and "lock" them with passwords, can summon up romantic prognostications simply by keying in a birthday, can chart their daily fortunes, keep track of their homework and important appointments, even check the time in London. And Casio's "Secret Sender 6000 With Magic Beam" not only serves as a remote control for TVs and VCRs, but can be used to send messages to a friend who also happens to have a Secret Sender 6000.

The diaries, which are the size of calculators, are available at the big toy outlets. But in the real world -- where the girls are -- they remain objects seen only on TV and as yet unpossessed Christmas wishes.

At Gaithersburg Elementary School, there is an audible intake of breath around the Formica-topped table as the diaries are presented, the low gasp of pre-adolescent yearning.

"I'm bugging my parents to get me one," 10-year-old Ann Korshy says, as half-a-dozen girls study the items.

"I want one so bad," says Chantal Bobbitt. "I would write all my personal stuff in it -- and about boys."

The lids are clicked open. Fingers poke at tiny buttons, eyes study the display windows. No one bothers to look at the directions -- no one needs to. Directions are for grown-ups. These 9- and 10-year-olds figure it out as they go along.

They plug in some dates. Ann gets a fortune: "You can't think of anything but the one you love." There are various jeers. Another, this time for Chantal: "Trouble getting on the same wavelength as your friend."

True, Chantal?

"Yes," she says. "Sometimes I'm bad and my friends get me into trouble if I follow their steps."

This is the virtue of fortunetelling. The actual fortune is insignificant -- it's all in how the words are heard.

And the medium helps. At least one girl suggests that the computerized fortunes are more reliable than those purveyed by folded-paper fortunetellers (you remember those four-sided constructions -- also known as "cootie catchers" -- that girls' fingers snap open and shut before lifting up a flap to reveal a fortune). "The computer might know more," says Sarah Brush, earnestly.

And even those who currently keep a diary, as several do, think there would be advantages to an electronic version. "It's harder," Sandra Rivera says of the kind that relies on actual pens and paper. "You try to write fast because someone's coming," especially if your lock is broken, as hers is. And there are other problems with actual paper, which never seems adequate to the passions and regrets of youth: "Sometimes you erase so much the paper might rip."

Of course, the plastic diaries do not allow for wordiness. Entries are limited to 40 or so characters. (The "Dear Diary ..." categories include a daily diary, a list of wishes, a shopping list, a list of favorite and least favorite things, and -- most importantly -- a list of up to 10 secrets, which the computer automatically puts in alphabetical order).

"Like everything else, it's a double-edged sword," says Diana Green, editor of the children's media guide Parents' Choice. "There's not enough space to write, but it's a way to get involved -- particularly for girls who may be more literary and like to write -- in computers. It might be an enticement into the computer."

Most of the girls around the table seem to need little enticement. Almost all say they are far more comfortable with computers and video games than their parents and even many of their teachers. Although they say boys remain more interested in video games than girls ("When they're born, they start acquiring them," says Ada Barker), they play with them also.

But the creators of Tiger's "Dear Diary ..." seem to have followed the toy industry's dictum that Girls Like Pastels, and their computer comes in a lavender case embossed with swirls and fuchsia lettering. The toy, which sells for $29.99 at Toys R Us, strikes several fourth- and fifth-graders as aimed at younger girls. "I think pink is more little kid-ish," says Sarah Brush. "It looks like it has makeup in it," says Monique Hall. "On TV, it looked like it had more buttons on it. I would like it if it were black."

These girls have outgrown pink. They prefer Casio's gray, turquoise and yellow case, and like that it can do more than Tiger's toy, what with its several different languages and what one girl calls its "greater capacity." It also costs more -- $59.99 -- but a few seem ready to put it on their list of wishes.

Before they leave, they type a few choice rumors and opinions into the diaries. They giggle, create a password and leave.