Gender diversity disclosures...on what basis?

The discussion about gender diversity disclosures this week piqued my interest.
NZ Herald article
Are these calls for gender and age disclosures simply representative of societal pressures towards inclusiveness, or are they because increased gender and age diversity is linked to increased company performance?
Researchers have been studying the supposed link between board composition factors and company performance for many years. To date, their findings are inconclusive. Gender diversity does, however, seem to lead to more civilised debate in the boardroom, higher accountabilities and better attendance. So, there appears to be goodness in diversity. However, we must to be careful not to confuse these inputs and activity with the desired output of increased company performance.
New Zealand was first to give women the vote, and that was good for society. Moving towards diversity in the boardroom may also be good for society. However, we don't know that yet. 
I applaud any move towards increased transparency and disclosure, particularly for listed companies. However, if the motivation is to move down a diversity pathway for which no solid evidence linking increased diversity to company performance is available, are we not on dangerous ground?
Follow the discussion on LinkedIn here.