The Cinderella Effect is a statistical tendency for child homicides committed by parents to be more likely to involve a step parent. Child abuse in general is more likely to occur with step children than biological children. Researchers have put forward a number of theories to explain this phenomenon and some challenge the Cinderella Effect, arguing that the statistics actually point to a higher likelihood of abuse in step families generally, and biological, as well as step children are at risk.
Researchers began identifying this issue in the 1970s, studying rates of child abuse and homicide in families in a number of developed countries including Sweden and the United States. Researchers found that child deaths often involved step parents, at a rate high enough to be statistically significant. Many also noted that in these murder cases, all children in the family experienced abuse, but step children often bore the brunt of it.
Evolutionary psychologists suggest that the Cinderella Effect is the result of a lack of interest in step children. Biologically, raising step children confers no obvious benefit, because those children don't carry a person's genetic material. Researchers critical of evolutionary psychology argue other factors may be at work to explain this phenomenon. Poverty can be a noted contributor to stress and violence, and many child murders can be linked with poverty, as well as step families. In addition, researchers note that disabled children in particular, biological or step, are at very high risk of being murdered or abused by a parent.
The findings of researchers interested in the Cinderella Effect are important. Identifying potential risk factors for child abuse and murder can help social workers intervene before a situation turns dangerous and can also play a role in making decisions about child custody in court cases. Making teachers and other people who interact with children aware of the issue can also be helpful, as it allows them to spot signs of abuse early.
Critics warn that the Cinderella Effect should not be taken as an indicator that all step parents are abusive. While there is a statistical link between step families and abuse of children, particularly step children, this does not mean step parents are inherently dangerous to the children in their lives. Many raise children in loving, supportive households very successfully. What the Cinderella Effect does indicate is the need for appropriate intervention in a step family where the parents are having arguments about the children, particularly surrounding issues like discipline.