Mark Regnerus laments that most religious teens are not saving sex until marriage, no matter how many pledges they make. In his book, Forbidden Fruit: Sex and Religion in the Lives of American Teens, he writes:

…few adolescents, no matter how religious, articulate a deep, nuanced sexual ethic. Although many religious traditions and texts suggest that sex is part of the good created order, that its connection to the human life is not accidental, that sex outside the context of a committed relationship harms both participants, etc., the only message most religious youth are getting is, ‘Don’t do it until you’re married.’ And this message does not go far at all toward shaping sexual decision making (207)

Along with that, Lauren Winner has written an article for the New York Times that states that making such commitments to wait without the grace of God and the context of the local church.