The aim of this work is to analyze the distribution of Duffy blood gro
up and the reproductive history of 148 malformed newborns and their mo
thers compared to 131 control pairs. The mother-child segregation of t
he system is analyzed using ITO matrixes. A higher frequency of hetero
zygote mothers for the system was found among the malformed group comp
ared to controls. No differences in the reproductive history was round
between Duffy system homozygote or heterozygote mothers.