Gender Parity as an Investment Strategy

There have been conflicting claims about whether the presence of women on corporate boards and in senior management improve the corporate bottom line.  Morgan Stanley is betting that it does; it is starting a "parity portfolio" that will invest in companies that have female representation on boards and cites research that "companies with significant female representation on boards and in senior leadership have stronger financials (return to shareholders, return on assets, return on equity, profit margins) than those that lack gender diversity in leadership."   According to a NY Times Dealbook column, this means companies with at least three women on their boards.  It strikes me that the portfolio won't be investing in a lot of companies!