CHIMERISM AS THE ETIOLOGY OF A 46,XX/46,XY FERTILE TRUE HERMAPHRODITE

Objective: To determine the conceptional events resulting in a 46,XX/46,XY true hermaphrodite and to report the first pregnancy in a 46,XX/46,XY true hermaphrodite with an ovotestis. Design: Chromosome studies were performed on patient lymphocytes and fibroblasts. Red cell antigens, human leukocyte antigens, and presence of Y-chromosome deoxyribonucleic acid were analyzed. Findings were compared with parental and sibling blood group data. Setting: Genetics clinic and laboratories of a university hospital. Results: These studies demonstrated that our patient is a chimera, with dual maternal and paternal contributions. In addition, despite the presence of an ovotestis, she conceived and delivered a child. Conclusions: The mechanism for chimerism in this case could be fertilization of (1) the secondary oocyte and first polar body; (2) the ovum and first polar body; (3) the ovum and second polar body; or (4) fusion of two embryos.