In contrast, in twins of African ancestry, no significant association between parental separation and timing of first sexual intercourse was observed in Cox analyses. Although it is possible that parental separation is unrelated to sexual timing, intact and separated African American families were poorly matched on family background characteristics highly predictive of separation, notably parental alcoholism. Poor matching was especially evident in the highest risk quintile, where no families remained intact, but parental alcoholism was over-represented. Together, such findings raise questions regarding the interpretability of survival-analytic results presented herein and thus the validity of between-family contrasts of intact and separated African American families reported in the broader literature. Thus, we are hesitant to draw substantive conclusions on what appear to be inappropriate comparisons.
