For the study of putative virgin pregnancies, researchers at the University of North Carolina at Chapel Hill analyzed data from the thousands of teenage girls and young women who took part in the long-running study. Download the new Independent Premium app Sharing the full story, not just the headlines Download now. Follow comments Enter your email to follow new comments on this article. One in mothers 'became pregnant without having sex'. Update newsletter preferences. The findings were based on a study of 7, women and girls aged 15 to 28, as part of the National Longitudinal Study of Adolescent Health, which ran from to Start your Independent Premium subscription today.