excluded from our analysis, the shared environment effect in males was no longer statistically significant (0.05, 95% CI 0.00–0.12, χ2 = 1.92, df = 1, p = 0.17). In females, the estimate of shared environmental effects was relatively large and marginally statistically significant (c2 = 0.16, 95% CI 0.00–0.33, χ2 = 3.06, df = 1, p = 0.08), and there was no heterogeneity across samples (χ2 = 8.24, df = 7, p = 0.31). When the common environmental parameters were equated across sex, excluding the Kaij outlier, there were no significant differences between the sexes (χ2 = 1.46, df = 1, p = 0.22).
