 Similarly, White Mexicans were quantified based on physical traits and appearance, thus technically a Mestizo with a percentage of Indigenous ancestry that was low enough to not affect his or her primarily European phenotype was considered to be white.Finally the remaining ethnicities, for being of a rather low number or being faiths have more permissive classification criteria, therefore a Mestizo could claim to belong to one of them by practicing the faith, or by having an ancestor who belonged to said ethnicities.Nonetheless, contemporary sociologists and historians agree that, given that the concept of "race" has a psychological foundation rather than a biological one and to society's eyes a Mestizo with a high percentage of European ancestry is considered "white" and a Mestizo with a high percentage of Indigenous ancestry is considered "Indian", a person that identifies with a given ethnic group should be allowed to, even if biologically it doesn't completely belong to that group.