Power of test statistics under an unbalanced sample design of different sex ratios in cases and controls. All parameters are equal in males and females. MAF = 0.3, prevalence = 0.1. RR = Relative risk. Results for recessive models: a 67% females in cases, 33% females in controls, model with X inactivation; b 67% females in cases, 33% females in controls, model without X inactivation; c 33% females in cases, 67% females in controls, model with X inactivation, and d 33% females in cases, 67% females in controls, model without X inactivation.