Mothers get caught between the prescriptive image of the ideal worker and the prescriptive image of the ideal mother.NEW DIRECTIONS FOR The glass ceiling in academia is well documented. Women are more likely than men to end up in non-tenure-track positions. Women on tenure track are less likely than men to be at four-year institutions. And highly ranked four-year institutions tend to employ low percentages of women (Mason and Goulden, 2002). Why?Part of the problem is gender bias, of two types. The more familiar is the glass ceiling that prevents successful women from reaching the summit of their professions. But what exactly is the glass ceiling? Typically, it is defined demographically, by documenting the dearth of women at the top. But why the dearth of women, when most academics (men as well as women) see themselves as committed to gender equality? Little information surfaces to help academic administrators who are determined to give women a fair shake.Many women never get near the glass ceiling because of a type of gender bias that has only recently been documented. In a 2003 law review article, a coauthor and I documented the "maternal wall" that inhibits women's progress once they become mothers (Williams and Segal, 2003). Mason and her team also have documented the sharp impact of having children on academic women's careers. Women who have children soon after receiving their Ph.D. are much less likely to achieve tenure than men who have children at the same point in their career. Prestigious research universities tend to grant tenure to men at a much higher rate, relegating women to secondtier teaching and adjunct positions (Mason and Goulden, 2002). The result is that most women who earn Ph.D.s never get near tenure, much less tenure at a leading institution.