Some physical traits that differ between sexes are known to be linked to certain single nucleotide polymorphisms (SNPs) in chromosomes other than the X and Y chromosomes, with each SNP representing a difference in a certain DNA building block in a particular stretch of DNA. New research now suggests that many of these “sex-heterogenous” SNPs also contribute to a person’s risk for a variety of diseases. Michela Traglia and colleagues at the University of California San Francisco, U.S. present these findings May 5th in the open-access journal PLOS Genetics.