Male antigen defined serologically does not identify a factor responsible for testicular development

To test the proposal that the serologically detected male antigen (SDMA; which may or may not be the same as H-Y) was responsible for triggering the indifferent gonad to differentiate into the testis in mammals, H-Y negative sex-reversed XXSxr' male mice were investigated for the presence of SDMA. Serum from C57BL/6 female mice immunized against tissue from XXSxr' males did not contain SDMA specific antibody as detected by the complement-mediated sperm cytotoxicity assay. Thus, although SDMA is a male-specific factor and may play a role in male sex determination, it does not identify the testis-determining factor (TDF).