That is incorrect. The sample consisted of 8,280 monozygotic (identical) and dizygotic (fraternal) twins. Twins separated at birth were not involved, if I'm rea

That is incorrect. The sample consisted of 8,280 monozygotic (identical) and dizygotic (fraternal) twins. Twins separated at birth were not involved, if I'm reading the study correctly. In any case, it's nothing worth arguing about. (I will say, though, that if there are 8,280 pairs of identical twins in Denmark who were raised separately, there is something very strange happening in Denmark.)