Uniparental disomy (UPD) is a rare genetic aberration characterized by the
uni- rather than biparental inheritance of a pair of homologous chromosomes
. Among the various adverse clinical effects that UPD can have in humans, a
bnormalities of the male reproductive system have been described in UPD of
the chromosomes 7, 11, 14 and 15, Given the considerable rate of sex chromo
somal aneuploidy in human gametes and zygotes, we postulated that paternal
uniparental disomy of the sex chromosomes might be a cause of otherwise une
xplained male infertility. With a set of highly polymorphic DNA markers the
parental origin of the X chromosome in 41 men with severe idiopathic infer
tility was determined, In all patients the X chromosome was derived from th
e mother, indicating regular biparental inheritance of the sex chromosomes,
We thus obtained no evidence that paternal uniparental disomy of the X and
Y chromosomes is a mechanism underlying idiopathic male infertility.