Because of an association between sexual aneuploidies and schizophrenia, and because schizophrenic siblings have been found to be more often of the same than of the opposite sex, the susceptibility locus for schizophrenia is thought to lie within the pseudoautosomal region of the sex chromosomes. We analysed 33 sibships comprising 18 pairs, 13 trios, and 2 quartets of affected siblings, and found support for non-random segregation of of alleles at the DXYS14 locus in affected siblings. These findings are consistent with the pseudoautosomal hypothesis for schizophrenia and favour a genetic linkage between DXYS14 and the disease.