One main disadvantage of diversity in the classroom is the problems it poses for teachers in their attempt to relate to students. In two separate studies, social scientists Ogbu and Harrison found an overwhelming majority of parents feel students should be taught by a member of the local community who shares their values. Students who attend school far from home may come into contact with teachers with radically different values, making values instruction difficult. Ogbu also found students must adhere to their school's dominant cultural values to perform at the highest level, which essentially makes them conform to a set of values and beliefs that may not be their own.
Diversity in school can also promote cliques that segregate children within a campus. While social subgroups are common in all schools, those with distinctly different minority groups may form more readily and along racial, social or economic lines. For example, if a school has 80% white students and 5% black students, the blacks may form a clique along racial lines, simply because skin color is their most obvious difference. Schools that are more homogenous will form cliques along non-demographic lines.
A huge problem with equalizing education is the language barrier, which poses problems for teachers who have students speaking different languages or a variety of dialects, or have different modes of expression. Teaching a classroom in which some students speak in the same way as the teacher and others don't can pose problems for teachers that they may solve by simplifying the curriculum or avoiding wordy or complex sentences, neither of which benefits their students.
Diversity will invariably lead to sensitive subjects in the classroom, including race relations, sexuality, politics, stereotypes and religion. For example, male teachers may feel uncomfortable teaching about sexual reproduction in females to a classroom of females and males. A less diverse classroom of only males could make the teacher feel more comfortable and less awkward about approaching the topic. Diversity can inhibit a teacher's ability to feel comfortable talking about topics and engaging students in a healthy debate.