Teachers play a big role in helping the child learn more about the world. In every subject, there is a minimum of 3-4 mentions about different races, ethnicities, or cultures, specially in subjects like political science. The more a child learns about these things, the more he/she will know the world which will mold his/her understanding of how things work. Lastly, I would say that it is often that we come across teachers encouraging their children to learn about people from different races, ethnicities, or cultures.