The risk of graft failure is highest for sex mismatched donors and recipients when the recipient body surface area is greater than the donor. Adjusted relative hazards for graft failure using combination of absolute body surface area difference (>0.03 m2 [D<R], 0.01–0.03 m2 [D<R], <0.01 m2 [D=R, reference category], 0.01–0.03 m2 [D>R], and >0.03 m2 [D>R]) and sex pairing (MDMR, male donor/male recipient; FDFR, female donor/female recipient; MDFR, male donor/female recipient; FDMR, female donor/male recipient). 95% CI, 95% confidence interval; D>R, donor greater than recipient; D=R, donor equal to recipient; D<R, donor less than recipient; HR, hazard ratio.