Mentoring programs provide benefits to mentors, proteges, and organizations, but not all organizations have such programs in place. In those that do, women's exclusion from informal networks limits their visibility and, in turn, their chances of acquiring a mentor. This poses a barrier to women's career advancement, as does the absence of female role models at senior executive levels. The biotechnology industry provides a context in which many women have penetrated the glass ceiling and reached the upper echelons of their organizations. The unstructured and dynamic nature of most biotechnology companies, along with the presence of women at the top levels of the organization, make an appropriate context for the implementation of formal mentoring programs to facilitate women's upward mobility.