Estimating familial variance components. The error bars denote the 95% confidence intervals. The diamonds indicating the estimates are scaled according to the mean number of children per family. The vertical green line indicates the weighted mean between the point estimates of the two cohorts (cohort #3 and cohort #4) based on the number of multi-offspring families each cohort contains. Variance component estimations for cohorts #1 and #2 were not included above due to small cohort size (Supplemental Fig. 2).