Sex while under the influence of youth

Controlling for age reverses the popular wisdom:  Living together before marriage doesn't cause divorce.  Doing so while under the influence of youth does.    Perhaps this explains why arranged marriages are fairly stable because adults are involved to set up and supervise until the bride and groom have grown up.   Being under 23 when you marry is a greater risk factor than cohabitation before the wedding.

The Council on Contemporary Families reports their findings.