[Serology and genetics of the Duffy-system (author's transl)].

Experiences in using anti-Fy(a) and anti-Fy(b) in paternity cases are described. Seemingly incompatible mother-child-pairs are due to a silent allele also present in whites. Dosage differences are inconstant and not fit to proof a single or double gene dose. Because of the uncertainty of genetical background the use of both Fy(a) and Fy(b) in paternity cases gives no more information than does Fy(a) alone.