It has recently been demonstrated that umbilical cord blood from genotypically human leukocyte antigen (HLA)-matched donors can provide sufficient numbers of progenitor cells for hematopoietic reconstitution. This technique has been successfully applied in the treatment of two children affected with Fanconi anemia (FA). Fetal cells from the potential sibling donors were first tested to determine that the fetus was not affected with FA. Unaffected fetal cells were then tested for HLA type. Cord blood from compatible donors can be harvested at birth and used immediately or frozen for subsequent use in hematopoietic reconstitution. We now show that fetal cell DNA amplification and hybridization for DQ typing can be an important adjunct procedure to verify serologically determined HLA class II types and/or to establish class II haplotype identity with the affected sibling.