Blacken, you could read the study because there was considerable discussion of those effects and various consistency checks that were explored. But you are right, this can't be done naively, and they didn't. Reading it, I had the impression it was carefully done and results were double checked in a variety of ways for accuracy.

Men for example are quite reluctant to label themselves as "abused" or raped so those words weren't used. Instead, many neutral behavioral de>

Ah, here's a link to the Lancet publication again:
Development of sexually abusive behaviour in sexually victimised males: a longitudinal study