Presence of female executives may negatively impact other women aspiring to senior leadership

Note, this is a scientific "theory", which is based on observations of actual data.

http://www.eurekalert.org/pub_releases/2015-11/w-pof111615.php

Public Release: 16-Nov-2015
Presence of female executives may negatively impact other women aspiring to senior leadership
Wiley

After analyzing 20 years of data on the S&P 1,500 firms, researchers have proposed a theory that women in top management face an implicit quota, whereby a firm's leadership makes an effort to have a small number of women on the top management team but makes less effort to have, or even resists having, larger numbers of women.

Therefore, the likelihood that a given position in a top management team is occupied by a woman is lower if another position on the same team is occupied by a woman.

The findings suggest that without efforts to promote greater gender equity in leadership positions, women may remain an isolated minority in top management.

"An important implication of these findings is that a firm's efforts to promote gender diversity in management may need to redouble, rather than relent, once the firm makes some initial progress," said Professor David Gaddis Ross, author of the study, which will be published in a special issue of the Strategic Management Journal.