Kin Groups and Descent. The Chuj reckon descent bilaterally. Each child has two surnames; traditionally, the first surname is the father's first name, the second surname is the mother's first name. In San Mateo, some families have adopted Hispanic surnames for men. Thus, a child would have an Hispanic surname from the father and a Chuj-style surname from the mother (i.e., her first name). The first male child is named after the paternal grandfather; the first female child is named for the maternal grandmother. The second male child is named for the maternal grandfather, the second female for the paternal grandmother, and subsequent children may be named for the parents. In large families, the names of the grandparents may be recycled, and, as a result, full siblings may have exactly the same names.
Kinship Terminology. Kin terms follow a bilateral pattern. Both sets of grandparents receive the same address forms and are equally "related." First-cousin marriage is discouraged; marriage with other cousins is permitted, although none is especially preferred. Grandparents and grandchildren use reciprocal address and namesake terms for each other. Women and men share the terms for parents and their siblings, grandparents, grandchildren, and distant relatives. The terms for children, brothers, sisters, cousins, spouses, and in-laws are gender specific. Men have separate terms for sons and daughters; women use a generic "offspring" label. Siblings are distinguished by relative age as well as by gender of the speaker. Twins are sacred and have special powers, but, even among twins, birth order ranks the pair; the younger always addresses the elder as superior.