From the New York Times:

In its filings with the Securities and Exchange Commission, Berkshire [Hathaway] explicitly states that it does not consider diversity when hiring board members: “Berkshire does not have a policy regarding the consideration of diversity in identifying nominees for director. In identifying director nominees, the Governance Committee does not seek diversity, however defined. Instead, as previously discussed, the Governance Committee looks for individuals who have very high integrity, business-savvy, an owner-oriented attitude and a deep genuine interest in the company.”