This is from the abstract from a research paper done by the University of Huddersfield into " Violence against children by step parents"
A wide range of child and caregiver characteristics, including parental psychopathology, parents’ childhood experiences of abuse, parenting stress, child age, parent age, child disabilities, socio-cultural background, and caregiver’s relationship to the child, have been reported to contribute to increased risk of violence directed against children. Although there is a dearth of research into violence against children in stepfamilies, some studies have indicated that stepparents are more likely to abuse children compared with genetic parents. Stepparents also have been found to pose a significantly greater risk of using excessive violence, which can subsequently lead to the death of a child. The risk of violence against stepchildren has also been found to be significantly elevated with the presence of stepparent’s genetic offspring. One possible explanation for increased violence in stepfamilies is that stepparents do not want to invest feelings and resources in children who do not carry copies of their genes. Sexual violence by stepparents, on the other hand, can be explained by the lack of exposure to a learning mechanism termed ‘incest aversion’, which refers to negative sexual imprinting during a critical period of early childhood to avoid inbreeding. Yet another possibility is that people who divorce are more likely to do so due to aggressive impulses which can play a part in relationship termination. When they remarry, those aggressive impulses can be directed against stepchildren. However, stepfamilies are also reported to experience more stressors associated with family violence, including alcohol abuse, child’s behavioral problems, adverse contextual backgrounds, and weaker social networks. This suggests that the stepfamily structure may not be a risk factor of violence against children per se. The purpose of this chapter is to provide a description of the problem of violence against children by stepparents, discuss the extent of the phenomenon and its possible theoretical explanations, critically review empirical research assessing violence against children by stepmothers and stepfathers, as well as suggest directions for future research.A wide range of child and caregiver characteristics, including parental psychopathology, parents’ childhood experiences of abuse, parenting stress, child age, parent age, child disabilities, socio-cultural background, and caregiver’s relationship to the child, have been reported to contribute to increased risk of violence directed against children. Although there is a dearth of research into violence against children in stepfamilies, some studies have indicated that stepparents are more likely to abuse children compared with genetic parents. Stepparents also have been found to pose a significantly greater risk of using excessive violence, which can subsequently lead to the death of a child. The risk of violence against stepchildren has also been found to be significantly elevated with the presence of stepparent’s genetic offspring. One possible explanation for increased violence in stepfamilies is that stepparents do not want to invest feelings and resources in children who do not carry copies of their genes. Sexual violence by stepparents, on the other hand, can be explained by the lack of exposure to a learning mechanism termed ‘incest aversion’, which refers to negative sexual imprinting during a critical period of early childhood to avoid inbreeding. Yet another possibility is that people who divorce are more likely to do so due to aggressive impulses which can play a part in relationship termination. When they remarry, those aggressive impulses can be directed against stepchildren. However, stepfamilies are also reported to experience more stressors associated with family violence, including alcohol abuse, child’s behavioral problems, adverse contextual backgrounds, and weaker social networks. This suggests that the stepfamily structure may not be a risk factor of violence against children per se. The purpose of this chapter is to provide a description of the problem of violence against children by stepparents, discuss the extent of the phenomenon and its possible theoretical explanations, critically review empirical research assessing violence against children by stepmothers and stepfathers, as well as suggest directions for future research.