Sorry, I worked for a government contractor. It may not be mandated, but we got regularly inspected for our "balance" by the government, and if we were way off it effected our ability to bid future contracts. When hiring, the HR dept would come to me and mention that they were concerned about the department "balance" and how the next hire would effect that. The implication is obvious, though no one would dare say it directly because you couldn't. They were just as worried about reverse descrimination litigation.
Potential loss of future business is practically blackmailing some businesses into removing whole classes of potential workers from each job. Been there, seen it.