Jack Werren's article featured in Highlights in Reproductive Biology

Males and females are made different through a diverse assortment of molecular mechanisms--from the XY chromosomal system of mammals to temperature-dependent systems in certain reptiles. In most species, some mixture of hormones, sex-specific transcription factors, and gene regulation carry out the initial instructions of the sex-determining triggers, but the outlines of these pathways have only recently begun to emerge in studies of various creatures.