Random Behaviour or Rational Choice? Family Planning, Teenage Pregnancy and STIs

Rational choice of teenage sexual behaviour lead to radically different predictions than do models that assume such behaviour is random. Existing empirical evidence has not been able to distinguish conclusively between these competing models. Using regional data from England between 1998 and 2001, I find that recent increases in availability of youth family planning clinics are associated with increases in teenage STI rates, but are not associated with changes in pregnancy rates for most age groups. I further find that the adverse impact on STI rates has increased significantly since emergency birth control has become more widely available. The observed relationships are largely consistent with economic models of rational choice and inconsistent with models in which teenage sexual behaviour is assumed to be random.