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.