In the history of Latin America over the last 500 years or so, the relationships among three races have been a key factor. In the beginning, there were the various indigenous groups. Then came the European colonizers, who later brought black slaves from Africa. The relationships among these racial groups have at times been tumultuous --- war, slaughter, subjugation, slavery, exploitation, miscegenation,...
The administration of the vast colonies was placed in the hands of nationals of the European empires. These administrators were rewarded estates for their efforts, and naturally inheritance rights became a significant issue. As a male may have multiple children with multiple women, the rights of these apparent heirs have to be defined, particularly when some of the mothers were not pure Europeans. Under Spanish rule, the following detailed caste system was instituted in Mexico at one time.
Mestizo: Spanish father and Indian mother
Castizo: Spanish father and Mestizo mother
Espomolo: Spanish mother and Castizo father
Mulatto: Spanish and black African
Moor: Spanish and Mulatto
Albino: Spanish father and Moor mother
Throwback: Spanish father and Albino mother
Wolf: Throwback father and Indian mother
Zambiago: Wolf father and Indian mother
Cambujo: Zambiago father and Indian mother
Alvarazado: Cambujo father and Mulatto mother
Borquino: Alvarazado father and Mulatto mother
Coyote: Borquino father and Mulatto mother
Chamizo: Coyote father and Mulatto mother
Coyote-Mestizo: Cahmizo father and Mestizo mother
Ahi Tan Estas: Coyote-Mestizo father and Mulatto mother
To us, this does seem to be a obsessive-compulsive behavior of an extreme sort. Today, the overt caste systems have been overturned by legislation, but that does not mean that social prejudices and economic exploitation are not present. Even though overt racial oppression is no longer permissible by law, people may still hold personal opinions about members of other races based upon preconceived notions.
Now much of this is premised upon one's ability to classify people into the appropriate racial categories based upon physical appearances. Unfortunately, this is difficult as there is not a clear-cut situation when any individual can be unambiguously classified into one (and only one) of a short list of racial classes. A simple classification scheme based upon color --- white, black, brown and yellow --- ignores the various shades.