There is a large swath of 20-something women who all appear to be afflicted with the same syndrome.

It shall be called Mollyphilia.

The Cult of Molly.

“I always wanted her glasses,” says Kristine Untalan, 23, a student at American University. “I faked poor eyesight. I was drawn to her nerdiness.”

“I always wanted her tap dance outfit,” Jessica Stewart says, wistfully. “I never got it.”

“When you choose Molly, you’re sort of putting a stake in a path,” says Stewart, 24, an art director for an ad agency. “It makes it more steadfast, who you think you are.”

In Korea, there is a custom called “doljabi,” by which parents predict their child’s future based on what object he reached for on his first birthday.

In the 1980s America of young girls — at least for a sizable portion — personalities could be determined by the selection of an 18-inch plastic doll, made by the Pleasant Company and marketed under the optimistic brand name American Girl.

Choose your doll, and show who you will become.

A quarter-century of history

American Girl dolls turned 25 this year.

An “experiential” store opened last weekend in Tysons Corner : 23,000 square feet of dolls. Dolls having their hair done in the doll hair salon downstairs. Dolls having their tea in the bright cafe upstairs. Dolls posed in historical tableaux: an American Indian doll with a tepee, a 1970s doll with a bicycle, a World War II-era doll with her pale, English-refu­gee friend.

Each of these dolls represents a different historical era.

Every historical doll comes with a set of six books recounting her adventures as a 10-year-old: what school is like, what birthday celebrations are like. This is the hook of the American Girl doll and why 20 million have been purchased. Girls are not buying dolls. They are buying whole personalities.

“I don’t know if there has ever — ever — been such an addictive marketing campaign, and I was way too young for the dolls, and I remember poring over the catalogue and coveting what I didn’t even understand. I remember the school desks. I couldn’t even imagine having such an amazing desk, and if there was a new accessory in the catalogue you would find it immediately, and you wanted one and you wanted one and you wanted one, and my mom said, ‘I am not paying $100 for a doll,’ ” Chiara Atik says.

Atik is 25, now a writer, now living in New York. A long time ago, she wanted, and eventually received, an American Girl doll. Felicity. “I can still remember,” Atik says, “what she smelled like.”

When the original line was released in 1986, it consisted of just three dolls: Samantha, Kirsten — a Swedish immigrant in the 1850s — and World War II Molly. Shortly after that, Felicity came, then Addy (an escaped slave), then post-Mexican independence Josefina, then Depression-era Kit, American Indian Kaya, Title IX Julie and Rebecca, a first-generation Jewish Russian American.

The story lines dealt with racism, women’s rights, workers’ rights and death, but virtuous lessons came with a price: Buying a doll and all of her accessories could cost $1,000. Some female culture critics have argued that one of American Girl’s primary contributions was teaching women how to catalogue shop.

All told, there are 10 historical dolls in rotation now. Many of their stories were either written or conceptualized by a children’s book author who lives in Silver Spring.

Her name is Valerie —

“Valerie Tripp?” Atik yells into the phone. “Oh, my God, you talked to Valerie Tripp? What was she like?”

Wonderful. Lovely. Sparkly. As wholesome as the plastic contents of Molly’s Lunchbox, available online for $20.

Cave-exploring girls

In 1973, Tripp was working as a writer for an education company that taught children to read. She had a co-worker named Pleasant Rowland, and they would talk about all of the girl-empowering books they used to read.

“We didn’t like the books where the girls said to the boys, ‘Don’t go in that cave!’ ” Tripp says. She and Rowland dreamed that one day they would write historical books for cave-exploring girls.

A few years later, Tripp got a phone call from Rowland, reminding her of the series idea. “She said, ‘Valerie, you worry about the books, because I’ve had another idea, which is that there will be dolls.’ ”

Tripp wrote all of the books for Molly, Felicity, Josefina and Kit, and half of the books for Samantha.

She tried to make each girl’s story arc parallel whatever was happening to America at the time.

“Felicity is a girl-size version of the American Revolution,” Tripp says. Molly learns the concept of sacrifice and self-sufficiency while the world around her erupts in Victory Gardens and scrap-metal drives.

“You just immersed yourself in that period,” Tripp says. “The music, the clothing, the toys.”

Rowland became the founder of a vast doll empire that she named the Pleasant Company and sold to Mattel for $770 million in 1998.

She doesn’t do interviews anymore. None at all.

“She just gets so many requests,” says her assistant, with the apologetic but weary tone of someone who has been tasked with guarding the pope.

Picking the right Girl

“I always thought Samantha was the prettiest,” says Amanda Scott, 26, who works in new media and lives in the District. “I was obsessed with her little” fur hat and muff set.

Samantha Parkington was an Edwardian-era orphan being raised by her wealthy grandmother in a New York suburb. Everyone thought Samantha was the prettiest, which made her an aspirational choice, and a little intimidating.

“A lot of my friends were Felicity girls,” says Meredith Jones, 26, a student at George Mason University, and those who know about American Girls will know exactly what this means.

Felicity girls had a greater likelihood of having red hair (Felicity did) and of loving horses (Felicity had one). Felicity’s story began in 1774 and lasted into the American Revolution. The girls who were Felicity girls probably yearned for independence but also loved the doll’s really pretty clothes.

However, “I do believe,” writes Jones, on her personal blog, “that the decision to get Molly over Samantha marked a turning point in my evolution as a woman.”

Yes. Back to Molly.

It was easy to get suckered in by the other dolls. Samantha and her pretty sophistication. Kirsten and her fat blond ringlets. Josefina and her pierced ears. All of these dolls — smart and vivacious as they were — would have sat at the popular table in the modern elementary school cafeteria.

Molly was different. Molly wore glasses. And plaid. In the book’s illustrations, Molly was relentlessly ordinary-looking. Her hair wouldn’t curl. Her socks were slouchy. Her pajamas were plain, striped button-fronts, unlike the frilly nightgowns worn by the other dolls.

Molly built bomb shelters under her kitchen table. Molly led her team to victory in Capture the Flag. Molly helped the war effort.

“Molly might have been my first act of rebellion, inasmuch as having a doll can be an act of rebellion,” says Jones, who got a Molly for Christmas one year. “There was an overabundance of girl toys in my life” — the Polly Pockets, the Barbies, the dolls with their own miniature makeup compacts and plastic boyfriends.

Traditional Barbie, she says, “is what I was acculturated to like as a little girl.”

Choosing Molly was stepping out of that paradigm. Choosing Molly was declaring that you would carry a purse only if it were big enough to hold books.

Whichever doll a girl chose said something about her but, more important, said something about her ability to choose — about the fact that she was developing a sense of what she valued and whom she wanted to be. The choice of one’s American Girl doll was a step toward independence, even if it happened in a doll-size shoe.

Changing American Girls

In 2008, the Samantha doll was retired, followed by Kirsten in 2009 and Felicity in 2010 (because Felicity was from Williamsburg, the Tysons Corner store carries some of her things). Girls can buy the books, but the dolls and their vast accessories emporiums have been archived, potentially forever. Molly remains, for now.

Instead of just historical dolls, girls now have the option to buy a My American Girl — a personalized creation assembled from various hair, eye and skin colors.

One could argue that this represents a me-focused generation of current American girls. They don’t want to learn history. They don’t want a doll that represents a ready-made personality. It’s either selfish, or it’s a sign of girls’ liberation.

At the Tysons Corner store, during a quiet moment the day before the grand opening, a store employee leads a wide-eyed early arriver through the store. The girl looks to be about 8 or 9. She is new to the American Girl line, and she has stopped by with her grandmother. They are carrying a box from Build-a-Bear, another experiential store in this mall.

The store worker leads the girl around, explaining all of her options. Perhaps she would like Kaya? Or Julie?

They arrive at a glass display case, featuring Molly in her striped pajamas.

“Molly is very adventurous and stubborn,” the employee says, confidentially. “She gets into lots of trouble with her best friend, Emily. Emily is English.”

The girl solemnly nods.

Sold.