The H-Y locus is on the short arm of the human Y chromosome in most individuals but on the long arm in at least one of 17 individuals with structural abnormalities of the Y.

To determine whether the gene that controls the expression of H-Y ("male") antigen on human cells is Y-linked, we have compared the H-Y antigen level in normal males with that in three males with two Y chromosomes. Leukocytes from one XXYY and two XYY males express more H-Y antigen than leukocytes from normal XY males. We conclude that a structural gene or positive regulatory gene for H-Y antigen is on the human Y chromosome. Testing for the H-Y antigen may be of benefit in patients who have signs of masculinization but who lack an identifiable Y chromosome. Positive results for the H-Y antigen would be tentative evidence that the corresponding region of the Y chromosome was present, perhaps as part of a translocation, despite the absence of a typical Y chromosome.