A term typically used with cultural anthropologists to describe a practice within a society or culture where the children of a couple with a differing socioeconomic status is automatically touted as a member of the lower class standing. For example, here in the States, if white person and a black person have a child, the child would typically be classified as black, not white.
Hypodescent is a term used in anthropology to describe the practice of assigning individuals of mixed ancestry to the group that is perceived as lower in status or privilege. This often occurs in societies where social hierarchy is based on race or ethnicity.