Final answer:
In bifurcate merging kinship, a parallel cousin refers to EGO's parents' same-sex siblings' children, who are considered siblings rather than cousins. This differs from cross cousins, who are children of the parents' opposite-sex siblings and can be potential marriage partners.
Step-by-step explanation:
A parallel cousin describes a type of consanguineal (by blood) relationship found in certain kinship structures, specifically within a bifurcate merging kinship system. In this system, EGO's parents' same-sex siblings are considered additional parents, thus their children are treated as EGO's brothers and sisters rather than cousins. For example, EGO's mother's sister's children and EGO's father's brother's children would be considered parallel cousins, effectively siblings in this context.
Contrastingly, cross cousins are the children of EGO's parents' opposite-sex siblings (EGO's mother's brothers and EGO's father's sisters). These are typically the individuals considered as cousins in this kinship structure and can be potential marriage partners in societies that follow bifurcate merging kinship practices. This system maintains a significant presence across generations and helps to segregate family members who can enter into marriage versus those who are considered too close, adhering to incest taboos.