In 1994, Martin Daly, Ph.D., a professor of psychology at McMaster University in Hamilton, Ontario, and his wife, Margo Wilson,
Ph.D. (who died after the study was completed), considered that paternity is of interest in cases of paternal filicide because
suspicions of nonpaternity may be germane to some cases, and the motivations in such cases may resemble more closely those
of steppaternal homicides. Stepfathers, compared with genetic fathers, are more likely to perpetrate lethal abuse of their
stepchild and never appear to commit suicide.