Stock price of companies declines with greater gender diversity

The July/August edition of the Harvard Business Review magazine has an interesting piece about the reaction of investors when women join the boards of companies. 

Although there are studies showing that companies with high numbers of female directors on their boards perform substantially better than those without diversity, the same cannot be said of what happens to companies' stock performance when more women join the board. 

According to this story by Andrew O'Connell, a group of researchers led by Harvard sociologist Frank Dobbin discovered that in the year after the number of women on a board increases, stock price tends to decline slightly. The researchers suggest that fund managers tend to associate men with leadership and react accordingly. 

Given the mess that approach got us into over the last couple of years, you'd think they would have altered that perception by now. But it would appear not. How depressing. And how stupid.