Work-life balance issues, which can be more challenging for women than men, should not be a barrier, says Ellen Johnson, treasurer and senior vice president at advertising and marketing company Interpublic Group, and the mother of three youngsters. A supportive partner and the willingness to put in the time, energy and commitment required, as well as to make trade-offs, can help women move forward, Johnson says. "I think things will change," she says, pointing to Interpublic's record as one of just six companies in the Fortune 500 with 40% representation of women on its board of directors.

Johnson says attaining a board seat would be a big boost to her career and she is encouraged by the opportunity to network in the office with Interpublic's women board members. She credits "the tone from the top" for making women directors a priority and says diversity is particularly important for a company in which people are the only asset. "We need to understand our clients, and our clients are completely diverse because we are a global company," Johnson says. "To have that perspective, you really need to have global inclusiveness at the top."