My research addresses evolutionary questions primarily in the area of sexual selection. One of the key questions I have been working on is the evolution of female mate preferences for exaggerated male sexual traits used in courtship display. The work is motivated by theory on the handicap principle (female choice of mates with higher phenotypic or genotypic quality) and Fisher’s runaway process (female choice for attractive mates). These ideas are being tested with Diopsid stalk-eyed flies, and this experimental work is in turn inspiring new theory about sexual traits and male fertility. In addition, my recent theoretical work has investigated sex determination and the evolution of gene networks, genomic imprinting of sex chromosomes, and the consequences of intra-genomic conflicts. I am a founder member and keen supporter of CoMPLEX, UCL’s inter-disciplinary research centre for mathematical biology.