My principal research interest can be summarised as the process and consequences of genetic damage in the male germ-line. Such damage can be induced by a variety of exposures, notably from therapeutic, occupational, recreational and environmental sources. This can have a variety of different effects on spermatogenic cells, including cell-cycle arrest, DNA repair, apoptosis or the fixation of mutations in the genome. These phenomena may affect the fertility or fecundity of the individual but can also result in the transmission of heritable mutation to the F1 generation. Conventionally, it is believed that spontaneously arising, mutations vertically transmitted in this way are the basis for evolutionary change, although the vast majority of observable mutations are deleterious. It is known that organisms are potentially exposed constantly to DNA-damaging agents both from endogenous and exogenous sources. However, it is not yet fully understood how or under what circumstances alterations occur in the germ-line or what might be their consequences.