This study indicates how a shift in the structure of kinship networks can create changes in both the content and valence of kinship relationships. The study compares the motherdaughter and the mother-in-law/daughter-in-law relationships, and the shift in their kin network consists of the birth of the daughter(-in-law)'s child. Findings from an exploratory research project, based on family case studies, suggest that orientation toward the child changes these relationships in different ways along three dimensions: interactive involvement, interpersonal boundaries, and relational strain. The orientation around the child appears to clarify the interpersonal boundaries between daughter and mother by shifting the mother's maternal role onto the daughter's child. But the birth of the child creates greater ambiguity in the quasi-kin, quasi-maternal relationship between mothers-in-law and daughters-in-law. Thus, the child seems to bring more relational strain to the in-law relationship and less strain to the mother-daughter bond.