"...Most diversity training efforts at American companies are ineffective and even counterproductive in increasing the number of women and minorities in managerial positions, according to an analysis that turns decades of conventional wisdom, government policy and court rulings on their head.
A comprehensive review of 31 years of data from 830 mid-size to large U.S. workplaces found that the kind of diversity training exercises offered at most firms were followed by a 7.5 percent drop in the number of women in management. The number of black, female managers fell by 10 percent, and the number of black men in top positions fell by 12 percent. Similar effects were seen for Latinos and Asians..." (source)
I think it's only common sense to realize that forcing (or requiring) someone to respect someone else is impossible and breeds resentment. Unfortunately the only way for people to become more accepting is by example (IMO anyway). Therefore if it's not there once they reach college/the workplace...I'm not sure if it can ever be taught. I think acceptance is something that has to be learned from childhood, not taught in a boardroom.