Genetic Variation: Species tend to out-breed in order to strengthen their genetic immunization. For instance there are certain diseases which are found among Asians or Europens, when a Erupoean and an Asian have a baby it’s possible that the baby is less likely to get both of the diseases.
Davis & Merton Hypothesis (1941) members of ethnic groups whose prestige in society is low would have better chances of marrying outside their group if they offered a high socioeconomic status in re-turn.
By-product Hypothesis (Kennedy,1944) : Intermarriage is more common between groups who have the same faith
Claude Levi Strauss (1949) Alliance Theory: Small groups must force their members to marry outside so as to build alliances with other groups.
Self Expansion Theory (Aron & Aron, 1986). The primary human motivation is to grow and expand the self. Individuals seek to expand the self in many ways including establishing relationships with others. According to this view, romantic relationships start when an individual perceives another person as an opportunity for rapid self-expansion. Aron and Aron (1986) wrote that “The self is expanded by whatever expands its potential efficacy-that is, by knowledge and the resources to apply knowledge. Forming a relationship with another person obviously offers knowledge and resources in abundance.” (p,28)
Future Generations: In-termarriage decreases the salience of cultural distinctions in future generations because the children of mixed marriages are less likely to identify themselves with a single group by intermarrying, in-dividuals may lose the negative attitudes they have toward other groups. (Kalmjin, 1998)