He compares the situation to that of a Swedish town that
simultaneously had a lot of storks and babies. "They decided
storks bring babies," Bearman says. "Actually, though, storks
breed in chimneys. So when there's an increase in
population—i.e., babies—there's an increase in houses, chimneys,
and thus storks. Babies and storks are independent things that
occur in this particular town simultaneously—like virginity and
good grades in a certain kind of person." In addition, Bearman
discounts the influence of virginity pledges on those declines
in teen pregnancy and abortions. He explains that pledges
succeed at delaying sex only within an extremely narrow set of
circumstances: if an adolescent is between 14 and 16, and if
she's part of a group that consists of no more than 30 percent
of the population where she's growing up. "The only way the
pledges work is if they draw kids into a moral community and
give them a sense of identity," Bearman says. Under these
circumstances, teens delayed having their first sexu