Context: Legislation has been proposed that would mandate parental notification for adolescents younger than 18 years (minors) obtaining prescription contraception from federally funded family planning clinics. Objective: To determine the extent to which parents are currently aware that their teenage daughters are accessing reproductive health services and how minors would react in the face of mandated parental involvement laws for prescription birth control. Design, Setting, and Participants: A total of 1526 female adolescents younger than 18 years seeking reproductive health services at a national sample of 79 family planning clinics were surveyed between May 2003 and February 2004. Main Outcome Measures: Proportions of minor females who reported that a parent or guardian was aware that they were at the family planning clinic and, under conditions of mandated parental involvement, proportions of minors who would access prescription contraceptives at family planning clinics or engage in unsafe sex. Results: Sixty percent of minors reported that a parent or guardian knew they were accessing sexual health services at the clinic. Fifty- nine percent of all adolescents would use the clinic for prescription contraception even if parental notification were mandated. This response was less common (29.5% )- among adolescents whose parents were unaware of their clinic visits and more common (79% ) among those whose parents were aware. Many adolescents gave more than 1 response to mandated parental involvement. Forty- six percent would use an over- the- counter method, and 18% would go to a private physician. Seven percent said that they would stop having sex as one response, but only 1% indicated this would be their only reaction. One in 5 adolescents would use no contraception or rely on withdrawal as one response to mandated notification. Conclusions: Most minor adolescent females seeking family planning services report that their parents are aware of their use of services. Most would continue to use clinic services if parental notification were mandated. However, mandated parental notification laws would likely increase risky or unsafe sexual behavior and, in turn, the incidence of adolescent pregnancy and sexually transmitted diseases. Context: Legislation has been rendered that would mand parental notification for adolescents younger than 18 years (minors) obtaining prescription contraception from federally funded family planning clinics. Objective: To determine the extent to which parents are currently aware that their teenage daughters are accessing reproductive health services and how minors would react in the face of mandated parental involvement laws for prescription birth control. Design, Setting, and Participants: A total of 1526 female adolescents younger than 18 years seeking reproductive health services at a national sample of 79 family planning clinics were surveyed between May 2003 and February 2004. Main Outcome Measures: Proportions of minor females who reported that a parent or guardian was aware that they were at the family planning clinic and, under conditions of mandated parental involvement, proportions of minors who would contact prescription contraceptives at family planning clinics or engage in unsafe sex. Results: Sixty percent of minors reported that a parent or guardian knew they were accessing sexual health services at the clinic. Fifty- nine percent of all adolescents would use the clinic for prescription contraception even if parental notification were mandated. This response was less common (29.5%) - among adolescents whose parents were unaware of their clinic visits and more common (79%) among those whose parents were aware. Many adolescents gave more than 1 response to mandated parental involvement. an over- the- counter method, and 18% would go to a private physician. Seven percent said that would would have having sex as one response, but only 1% indicated this would be their only reaction. One in 5 adolescents would use no contraception or rely on withdrawal as one response to mandated notification. Conclusions: Most minor adolescent females seeking family planning services report that their parents are aware of their use of serviceMost, continue to use clinic services if parental notification were mandated. However, mandated parental notification hazards would likely increase risky or unsafe sexual behavior and, in turn, the incidence of adolescent pregnancy and sexually transmitted diseases.