Why do so few women occupy positions of power and prestige in every field? To achieve parity we have to know what the problems are as well as what the problems are not. The data show that there has been progress but that a stubborn problem remains: advancement is slower for women than for men in every profession. That stubborn problem is not (or not solely) due to too few women in the pipeline, inequitable childcare arrangements, or women's "choosing" to leave the professions. Rather, the ubiquity of women's slow advancement requires a general explanation through the concepts of gender schemas and the accumulation of advantage. Gender schemas lead both men and women to see men as more competent and able than women, to respond more favorably to male than female leaders, and to attend and defer more to men than to women. Many of the cases in which a woman is disadvantaged are of small scale. The notion of the accumulation of advantage demonstrates how even small-scale disadvantages can mount up over time. The gender schemas analysis allows us to devise appropriate remedies at the institutional level and at more individual levels.