In many animal species, embryos are exposed to maternal hormones that affect their development. Maternal hormone transfer varies with environmental conditions of the mother and is often interpreted as being shaped by natural selection to adjust the offspring to prevailing environmental conditions. Such hormone transfer requires genetic variability which has not yet been experimentally demonstrated. Our study reports direct evidence for additive genetic variance of maternal androgens through a bi-directional selection on yolk testosterone (T) levels in Japanese quail. Lines selected for high (HET) and low (LET) egg T concentration differed in yolk levels of this androgen resulting in high realised heritability (h2 = 0.42). Correlated responses to selection on other gonadal hormones indicate that selection specifically targeted biological active androgens. Eggs of HET quail contained higher androstenedione and lower estradiol concentrations than those of LET quail, with no line differences in yolk progesterone. Plasma T concentrations of adult females were not affected by selection, seriously challenging the hypothesis that transfer of maternal hormones to offspring is constrained by hormone levels in a mother's circulation. Our results suggest that transfer of maternal T represents an indirect genetic effect with important consequences for the evolution of traits in offspring.