SOME INGREDIENTS IN THE STEAMING HORmonal stew that is American adolescence: For Prom Night last week, senior class officers at Benicia High School in California assembled some party favors — a gift-wrapped condom, a Planned Parenthood pamphlet advocating abstinence and a piece of candy. “We know Prom Night is a big night for a lot of people, sexually,” senior Lisa Puryear told the San Jose Mercury News.