Autosomal recessive or sex linked recessive: a counselling dilemma.

This paper discusses the difficult problem that arises when information is sought by female relatives of two or more brothers, each of whom has an identical but undiagnosed or 'new' syndrome, which is likely to be either autosomal recessive or sex linked recessive in inheritance. It is proposed that standard Bayesian methods may be applied in this situation thus incorporating the prior probability for each event with conditional probabilities based upon pedigree analysis.