Do my parents have to know?" the teenage girl's voice asks fearfully on the telephone. Debra Haffner, a staffer at Planned Parenthood in Washington, D.C., reassures the girl calling for an appointment that birth control counseling is confidential. What Haffner can't guarantee, however, is how much longer that will be true.

Sexually active teenagers are already reacting with alarm to a regulation proposed by Secretary of Health and Human Services (HHS) Richard Schweiker that could profoundly affect their lives. As drafted, the rule would require any clinic that supplies a girl under 18 with federally financed birth control pills, an IUD or a diaphragm to notify her parents within 10 days. Though still under administrative review, and months away from implementation, the regulation has triggered an emotionally charged debate. The usual request for public comment drew an extraordinary response—a torrent of 40,000 letters, most of them opposed to what detractors call the "squeal rule."

The regulation's chief proponent is Marjory Mecklenburg, 46, who heads the Office of Adolescent Pregnancy Programs at HHS. In her view, the proposed regulation would "break down the barrier that separates parent from adolescent" over teenagers' use of contraceptives. Arguing that birth control devices—at least the Pill and IUDs—pose a health risk to teenagers, Mecklenburg says that failure to consult parents amounts to an abrogation of their rights. "Without consent, children cannot have their ears pierced or get a shot from the school nurse," she says. "Yet somehow, uniquely in the area of contraceptive services, we have closed the parent out."

Originally a home economics teacher in Minneapolis, Mecklenburg put her career on the back burner to raise a family of three sons and a daughter, now ranging from 25 to 15. Her husband of 27 years, Fred, an obstetrician and gynecologist, first engaged her interest in the abortion controversy 14 years ago. "The thing that really touched me," says Mecklenburg, "was the actual pictures in the obstetrical journals of the developing fetus and the difficulty of drawing a line and saying, 'This life is not expendable after today, but yesterday it was.' " Having made her reputation by helping to form anti-abortion groups, Mecklenburg was recruited by the Reagan Administration for her present $55,000-a-year job. Husband Fred was unusually supportive, taking a leave of absence from his medical practice in Minneapolis to join her in Washington. While she defends her position by stressing that contraceptives are "potentially dangerous drugs and devices," Mecklenburg concedes that she would prefer to see less sexual activity among young people. She believes that more involvement by parents would slow the national epidemic of teenage pregnancies—more than one million in 1981.

Mecklenburg's opponents denounce the proposal as a devious and misguided effort to legislate teenage chastity. "They're not really interested in the health care of these young people," declares Faye Wattleton, 38, president of the Planned Parenthood Federation of America. "The real intention is to discourage the young from using those services and thereby force them not to be sexually active." Calling the health and safety rationale for the regulation a "smokescreen," Wattleton points out that clinics would not be required to report venereal disease among teenagers, even though the death rate for penicillin treatment is twice that for birth control pills and IUDs. Wattleton's organization has pledged to retain confidentiality for teenage clients of its 5,200 clinics—even at the risk of losing $30 million in federal subsidies. She predicts that teenagers, rather than allowing their parents to be advised that they are having sex, would instead simply stop using contraceptives. "What the regulation means in reality," she says, "is that more young people will become pregnant."

Wattleton, a former nurse and the divorced mother of a 6-year-old daughter, became active in Planned Parenthood 14 years ago because, she says, "I felt it was doing something to prevent needless suffering—young women facing unwanted pregnancies, the tragedies of illegal and unsafe abortions."

Two months ago a survey of 400 teenage clients by the main Planned Parenthood clinic in Chicago indicated that they oppose the proposed regulation by a substantial margin of 7 to 1. "Many teenagers simply felt that their parents wouldn't understand their sexual activity and their need for contraceptives," says Barbara Shaw, a Planned Parenthood staffer in Chicago. A Washington teenager who opposes the requirement says the Reagan Administration should redirect its focus. Instead of restricting adolescents, she says, the government should pass a regulation for parents: "Go to class to learn how to talk to your kids!"