Familial investigation features prominently in forensic science within both the criminal and civil jurisdictions. This chapter reviews the application of autosomal short tandem repeat evidence to parentage testing and discusses the issues associated with mutation, null alleles and genetic anomalies. It focuses on pedigrees involving one or two alleged parents and one or more children. In a criminal context such testing can be required following sexual assaults, for example to identify the father of a child conceived as a result of an alleged assault. During civil litigation familial investigation can be used to substantiate claims by an estranged partner for financial support and maintenance of a child. In many countries it is common for the scientist to be presented with samples from a pregnancy termination procedure. In some criminal cases, the complaints are retrospective and the only samples from a foetus may be in the form of archival histology samples.