Second, we were not able to simultaneously estimate all the possible genetic correlations within our model. This could result in a bias in our parameter estimates, if qualitative effects were present. Such a bias would likely effect parameter estimates more seriously in females as they are less precisely known than in males due to the sex-related prevalence differences in externalizing syndromes. We were able to explore in a limited and tentative fashion the large parameter space and gain some insight into the possible presence of qualitative sex effects.
