The authors state "One possible explanation for this relationship is that teens in more religious communities may be less likely to use contraception". For example:
Rosenbaum compared adolescents who reported taking a virginity pledge with a matched sample of nonpledgers . Among the matching variables was pre-pledge religiosity and attitudes toward sex and birth control. Pledgers did not differ from nonpledgers in lifetime sexual partners and age of first sex, but pledgers were less likely to have used birth control and condoms in the past year and at last sex.So much for sex education which promotes abstinence as a viable form of contraception. And how astonishing that international aid organisations like Catholic Relief Services still see abstinence education as a key weapon in their fight against HIV/AIDS.
Another case of illogical beliefs resulting in very logical (and tragic) outcomes.