Chastity Pledges and Risky Sex

From the department of ambiguous scientific studies deployed to make political claims comes this latest summation by Wrey Herbert:

Bornovalova and her colleagues crunched all the data together, with provocative results. They did in fact replicate the well-known link between early sexual initiation and later sexual risk taking. But there was no evidence that an early loss of virginity actually caused risky sexuality later. Indeed, twins who had very different initiations into sex — one early and one late — nevertheless went on to have similarly risky sex lives, indicating that risk taking was influenced by some combination of shared genes and experience.

What counts as “early” and “late” in terms of “initiations into sex”?   The closest we get is that some people report their first sexual encounter before the age of 16.  The rest, “later.”  16 and 1/2?  17?

But the most perplexing line is the final one:

Lawmakers and pastoral leaders may have their own reasons for wanting to delay kids’ sexual experience, but their alarms about promiscuity and pregnancy just lost much of their power.

Wray seems to be suggesting that the failure of chastity pledges to actually prevent sex undermines the “alarms” that lawmakers and leaders have about young adult sexual activity.  Almost as though the failure of laws to prevent stealing in some cases undermines the strenuous objection to it and the efforts to prevent it.