original_query: What is the hypothesis regarding fetal microchimerism and its involvement in SS pathogenesis?
query: What is the hypothesis regarding fetal microchimerism and its involvement in Sjögren's syndrome pathogenesis?
answer: Increased incidence of Sjögren's syndrome (SS) after childbirth suggests a link between SS and pregnancy, leading to the hypothesis that fetal microchimerism may be involved in SS pathogenesis.  Studies have shown the presence of Y-chromosome-positive fetal cells in the salivary glands of women with SS, supporting this hypothesis.