Kinship is a core aspect of anthropological theory and ethnography. Traditionally, anthropology focused on its procreative quality, even though non-procreative practices were present in the ethnographic record. I contend that the problem was mostly at the ethnographic level, since the practices were not dealt with as kinship forms. Most were approached in contexts of patronage, spirituality, sponsorship and so on. They were therefore not analyzed according to the same criteria by which procreative forms were analyzed, even though there were hints of a resemblance to kinship. My recent systematic field study among Gulf Arabians led to the discovery of a widespread non-procreative practice which in fact shares all the core elements identified as characterizing procreative kinship. The significance of this find lies in allowing nonprocreative forms to be included along with procreative kinship, thus transcending the biology-culture divide and opens analysis to a necessary feature of flexibility that allows for cross-cultural variation. The features that define a set of relations as kinship relations are summarized in terms of two dimensions, namely ancestry and continuity. Both ancestry and continuity are ensured and are institutionalized by having a formal set of terms identifying relatives (known as kinship terminology), by ‘corporately’ sharing wealth, and/or name, and/or honor, and/or responsibility, and/or identity, and by having culturally recognized rules of avoidance (incest rules). Those are the parameters that define a set of social relations as kinship.