In ruling on the over-the-counter status (OTC) of the emergency contraceptive, "Plan B", the US Food and Drug Administration (FDA) questioned whether younger adolescent females could adequately self-select and self-medicate. That determination requires a judgment of fact, regarding how increased emergency contraceptive availability would affect adolescents' behavior, and a judgment of values, regarding the acceptability of different outcomes. We present a general approach to such problems, using analytical and empirical methods grounded in behavioral decision research. We illustrate it with findings from 30 in-depth interviews and follow-up surveys, with adolescent females aged 13-19 in the Pittsburgh area reporting how Plan B availability would affect three decisions (having sex, choosing contraceptives, using Plan B). Although the FDA expressed concern about younger teens using Plan B as their primary form of contraception, neither younger nor older teens revealed such an intention. However, teens preferred easier availability, should emergency contraceptive be needed. Incorporating an understanding of teens' decision-related perspectives can make such policies more predictable and transparent.