Ambilineality

Societies practicing ambilineal descent are especially common in Southeast Asia[2] and the Pacific Islands.

There is no set order in an ambilineal system to which the last name is chosen, and individuals may use both parents as links to a kin.

Societies may have a law or cultural customs determining whether to trace descent through the mother or father for a child's surname.

Emphasis on descent through the female line came about because of people's interest in whitening their lineage since Brazilian women frequently married white European immigrants.

It was due to the Iberian concept of “purity of blood” (Spanish: limpieza de sangre) and their dislike of “infected” races such as Jews or Moors.

[12] The flexibility of the descent group enables people to exercise a greater choice in their behavior towards kinsmen, especially distant kins.

[15] There is an ambilineal naming system in Spain and many Latin American countries, but with an implicit patrilineality.

However, it was the cultural tendency to use both the mother and the father's surnames following the general Spanish practice.

[16] In the Tiwa, it is a “personal choice” whether to live in the mother or father's home, indicating which “clan” they will join.

Based on this choice, the children inherit the mother or father's surname when born into the respective clans.

While ambilineal kinship terminology is oftentimes described as either generational or using cross-generational relative age criterion, there is some push back on these ideas.

The Portuguese were concerned about the purity of blood, (see: limpieza de sangre) because of Jewish persecution and brought these ideas to Brazil.

The Portuguese husbands provided more whiteness for the offspring, but the children would typically adopt the maternal surname if the wife's family were wealthier and more established.

[21] Ambilineal descent also occurs amongst the Tegrefifin speakers who border the Amhara to the north although they have a clear bias in favor of the men.

[22] Amongst the Christian Abyssinians, marriage happens outside the first seven degrees of consanguinity and work hard to live up to this rule.

[24] In the Tiwa (Lalung) people who live at the Assam-Meghalaya border area in India, ambilineal descent is evident through their marriage and residence practices.

Membership and affiliation to a descent group is expressed via surname (and domestic belonging/residence associated) as well as connection to deities.

At birth a child inherits the house's descent group and the bonds that have been established between the god inhabiting the home.

In the Northern Gilbert Islands ambilineal descent systems are evident in both Butaritari and Makin.