Invited review: sex-based differences in gene expression.

Certain diseases are more prevalent among women than men. The reasons for this increased prevalence are unknown, but there could be a genetic basis. Increased expression of X-linked genes in females, protective effects of Y-linked genes in males, or sex-limited gene expression that is developmentally or hormonally regulated could all account for these differences. Analysis of individuals with and without genetic sex reversal provides a means for distinguishing between genetic and hormonal causes. This can be complemented by genetic linkage and gene expression profiling to aid in the identification of candidate genes.