In 1978 and 1979, the Paedophile Information Exchange surveyed its members and found that they were most attracted to girls aged 8–11 and boys aged 11–15. In 1978, Glenn Wilson and David Cox approached O'Carroll with a request to study the PIE membership. A meeting was held with the PIE leadership to vet the survey instruments and, after approval, these were distributed to PIE members in the course of their regular mailing. Wilson and Cox went on to use the data in writing their book, "The Child-Lovers – a study of paedophiles in society".