This quote is likely referring to research studies that have found a positive correlation between gender diversity on corporate boards and various measures of financial performance. Here is one example of such a study:
In 2015, the Peterson Institute for International Economics conducted a global survey of 21,980 publicly traded companies in 91 countries. The study found that companies with at least 30% of women in leadership positions (including board members and C-suite executives) had net profit margins that were on average 6 percentage points higher than companies without any women in leadership positions. Additionally, companies with women on their boards had lower levels of debt and tended to be more innovative.
This study and others like it suggest that gender diversity on corporate boards can lead to better decision-making, improved risk management, and greater innovation, which can in turn lead to better financial performance.