Alex KUCZYNSKI, She's Got To Be A Macho Girl. John Bernard is 16, strapping, handsome, a hormonal hot pocket of a teenager. Guys like him were once every father's nightmare. No longer. "The girls are way more aggressive than the boys," John said during his 11 a- m- lunch period recently at the School of the Future on Lexington Avenue and 22nd Street in Manhattan, as a half-dozen girls buzzed around him. "They have more attitude. They have more power. And they overpower guys more. I mean, it's scary." After a half-century during which generations of young women were advised to never even call a boy on the telephone, it is now teenage girls who not only do the calling, but who often initiate romantic and even sexual activity. Whether they are influenced by the effects of feminism, which has taught girls to be assertive in all areas of life, or have internalized the images of sexually powerful women in popular culture, American girls are more daring than ever. "The teenage boys I see often say the girls push them for sex and expect them to ask them for sex and will bring it up if the boys don't ask," said Tabi Upton, a counselor at the Johnson Mental Health Center in Chattanooga, Tennessee, who consults with 20 to 30 teenagers a month. "There has been a shift where girls now see themselves as sexualized and approach men with pretty much the attitude, This is all I have to offer." Teenage girls have always chased and flirted with boys. But now they are initiating more intimate contact, sometimes even sex, in a more aggressive manner, according to many counselors, psychologists, magazine editors and teenagers. Sarah Durrell, 17, a high school girl in Massachusetts, said that all her friends consider asking out a guy normal. "No one is a stay-at-home mom anymore," she said. "Women don't have to wear skirts. We are empowered and we can do whatever we want." Her mother approves, she said. Her father does not. Sarah said, "He always says, ' I used to be a boy once and I know what they're after and they're only after one thing.' I guess he is an old-fashioned dad." Many girls attributed their forwardness with boys to the gains of feminism, which promotes parity between boys and girls in fields like sports and education. The message of empowerment has been translated by 15-year-old girls into the worlds of dating and sex, and while many girls approve, some of their elders are skeptical. "Girls have been told in every part of their lives to go for it," said Atoosa Rubenstein, editor in chief of CosmoGirl, which is aimed at readers 11 to 17. "Their mothers have told them, Go for student council, go for the team, go for that job, and that has turned from a message directed toward achievement to being something their whole lives are about. So they apply it to pursuing boys as well." Whether that pursuit is sexual or an expression of a crush, Ms. Rubenstein said, "is up to the girl." Research data about sexual activity among teenagers show a conservative trend, at least in terms of intercourse. The percentage of high school students who remain virgins has climbed steadily over a decade, to 54 percent in 2001, according to the Centers for Disease Control and Prevention. Of students who are sexually active, a declining share report having had four or more partners. The reasons for the trend, experts say, include fear of AIDS, the rise of sex education that teaches only abstinence and the increase in oral sex, which many teenagers think of as less intimate than intercourse. As girls come to equal boys in student government, honor societies and athletic teams, they are also behaving much more like boys, said Dr- Ann Kearney-Cooke, a co-director of the Helping Girls Become Strong Women Project at Columbia University. Several studies show that girls are smoking and drinking as much as boys are. Marty Beckerman, 19, a student at American University in Washington, said that girls' sexual bravado is a response to the cold transactional nature sex has taken on for some. "There is a kind of machismo among girls now," he said. "They have the male-conquest attitude." Monie Begley, a public relations executive, said that her 16-year-old daughter, Caitlin Feurey, summed it up for her recently. "She looked at me and said, `Well of course we ask boys out,"' Ms. Begley said. "And she tilted her head to one side and looked at me as if I was crazy and said: `Come on. We're equal now."'