Forget the boys. Albeliza Perez and her new classmates have hardly missed them ever since they arrived here at the Young Women's Leadership School, the nation's latest and boldest gamble on same-sex public education.

Now they waste no time flirting in class. Or fretting as much about their hair or clothes. Or fighting as often for the attention of teachers. Or, as Perez, a seventh-grader, bluntly put it, "groveling all day at the feet of some guy."

"Some of my friends don't understand this. They say, How are you ever going to get a boyfriend now?' " she said. "Well, you have until you die to pick up a guy, right? I don't want to worry about it every day at school. Here I can concentrate on my work."

Across the nation, public educators are looking anew at the differences in how boys and girls learn and examining whether keeping the sexes apart in schools or class could spur academic achievement, reduce sexual pressures and improve their self-esteem, as some recent research on the subject suggests.

That view is prompting schools nationwide, and in the Washington area, to reconsider the one-size-fits-all, fully integrated model of public schooling and experiment with same-sex classes, either for disadvantaged minorities or for girls in subjects such as math or science that traditionally have been dominated by males.

But few projects are as ambitious as the one underway here on three gleaming floors of a transformed office building of East Harlem. It is one of the nation's only all-girl public schools, and its opening this month -- over the furious objections of some feminist and civil liberties groups -- is a sign of an important new mood affecting public education.

"There's a lot of rethinking about the whole idea of the common public school and whether it's absolutely right for everyone," said Diane Ravitch, a public education scholar at New York University who served as an assistant education secretary in the Bush administration.

"No one wants an entirely separate system, but on the other hand there are real differences between boys and girls. Schools are acknowledging that more, and looking for some voluntary ways to address it."

The debate over same-sex education is taking place despite a Supreme Court ruling this summer that strongly affirmed the importance of gender equity in education. The court, in a case that examined the all-male, publicly supported Virginia Military Institute, decided 7 to 1 that such a school is unconstitutional unless states are "evenhanded" in the educational opportunities that they offer men and women. Yesterday VMI voted to admit women for the first time in the school's 157-year history.

In New York and other cities considering ideas like the Young Women's Leadership School, education officials say they are confident they are on firm legal ground. Offering some girls a separate but equal school with the same amount of funds, they argue, does not necessarily deprive boys of educational opportunities and so falls within the court's ruling.

Decades ago, there were a handful of same-sex public schools in some cities, but virtually all of them became coed after the civil rights movement of the 1960s. The last all-girls public school here in New York closed in 1986. Opponents of the Young Women's Leadership School say they fear it could set a precedent for an array of new public schools designed to teach not just girls or boys but also particular racial or ethnic groups.

"Regardless of how good their educational intentions are, public schools cannot segregate by gender or by race," said Norman Siegel, executive director of the New York Civil Liberties Union, which has filed a formal complaint with the U.S. Department of Education objecting to the new all-girls school. "The focus should be on improving integrated public schools. But what they're trying to do is turn the clock back."

Other critics fault the new school for different reasons. Some say it fosters a stereotype that young boys are an intrinsically bad influence on girls. Some also contend that suggesting girls have to be taught outside the company of boys to reach their academic potential is demeaning and ignores the root cause of their problems in traditional public schools -- poorly trained teachers, or poorly supervised boys.

But other public school officials point to the academic success of private schools, many of which have same-sex classes, to make their case for it. Some school districts in northern Virginia recently have begun limited experiments with same-sex classes. Higher education officials are also seeing the trend: Enrollment in women's colleges nationwide has increased for five consecutive years. "This is an old idea whose time has come again," said Ann Tisch, one of the school's founders. "So many studies say things start to unravel academically for many girls -- and boys -- once they reach junior high. We're not trying to pamper any of these girls. We just want to address some of the problems they have in other schools."

Recent studies have shown that girls and boys tend to respond to different teaching styles. Four years ago, the American Association of University Women also issued a report that concluded sexual bias was a serious problem in many schools. It suggested that teachers often pay more attention to boys than girls and at times discourage girls from pursuing careers in math or science. The report also found that girls face significant sexual harassment in middle and high schools.

The girls who are part of the new all-girls public school here in East Harlem, a working-class neighborhood of Hispanics and blacks, say they can attest to all of that. One recent morning, during a break from math class, Perez and Kimberly West, 11, recounted a lengthy list of frustrations with how boys -- and in some instances teachers -- had treated them in their other public schools.

"The boys dominated most of the classes," West said. "Sometimes I didn't want to ever raise my hand and ask questions."

"Especially with the male teachers," Perez interjected, "there was all that male bonding stuff."

"Here you can invent a whole new character," West said. "Girls get to be in charge of everything. You're not thinking all day, God, do I look okay?' "

"There's not all the teasing," Perez said. "At my other school, some girls worried so much about boys calling them fat they wouldn't even eat."

They said the Young Women's Leadership School looks and feels nothing like their other schools. Classes here are small -- they usually have less than 15 students. Instead of sitting at desks lined in rows, students gather around small tables, because research shows that girls prefer to learn by cooperating -- not competing -- with each other. Classrooms are relaxed and quiet. There are no bells. A teacher's presentation unfolds more like a conversation, not a chalkboard lecture.

Every student wears a blue blazer and pleated skirt; it is a requirement. A few male teachers drop by every week to teach music or chess, but most of the time the only men in sight are making deliveries. The staff is virtually all female.

A subway track rolls right next to the school, but the rumble and squeal of the trains are difficult to hear over the classical music that plays all day in halls and classrooms. Some walls are painted pink. Each table in the cafeteria has a bright flower setting. In the front office, there are books for parents: "Girls and the Physical Sciences," or "Raising Competent, Confident Daughters."

The school is funded like any other public school here. It uses the city's standard curriculum, but stresses math and science. Teachers also promote women's themes in some courses. In Madelene Geswaldo's humanities class the other day, a lesson on the Middle Ages led to discussion on the role of women, and that led to a chat about what limits the girls should set when trying to please the boys they like. "We want to give them a chance now and then to talk about those things, too," Geswaldo said. "It's a real relief for them."

This fall, the school only has space for 50 seventh-graders. The city intends to add a grade each year until it is a high school for several hundred girls. But already the Young Women's Leadership School has scores of girls on its waiting list. Parents of girls who are years away from being eligible to attend the school call every day hoping to get an early jump on future openings.

The first class of girls here are mostly Hispanic or black and live in the neighborhood. Each applicant was interviewed. Preference was given to girls from disadvantaged backgrounds who had strong academic records.

Girls also were asked about books they had read and wanted to read. The school is stocking its library with their choices. Parents say they like personal touches like that.

Janitzea O'Neil, whose daughter Carla attends the school, said she was impressed that her daughter was questioned more about her aspirations than her test scores when they visited this summer. "They really tried to get to know her," O'Neil said. "You don't have that feeling in many of the regular public schools." The school's principal, Celenia Chevere, grew up in East Harlem and said many students there deserve a better public education than they get. "Public schools just get stuck into doing the same old things," she said, "and they don't have a mission. We do -- to help these girls learn and become leaders." CAPTION: Gigi Grasso, left, Kara Benson and Jenny Freites work on the floor at Young Women's Leadership School. CAPTION: Albeliza Perez, center, and friends examine needlework at all-girl school.