Parentage testing implications of male fertility after allogeneic bone marrow transplantation

Fertility is expected to be reduced after the extensive chemotherapy and/or radiotherapy that is needed for conditioning prior to bone marrow transplantation. However, a male patient can be fertile, and in very rare situations such as reported here, this may confuse subsequent paternity testing. The patient, initially excluded as the biological father by red cell types but not by HLA, was subsequently included after the history of his previous marrow transplant was revealed, a review of the HLA results and further RFLP testing on buccal mucosal cells. This case points to the need for good history taking before performing paternity testing.