It’s called the Cinderella effect — a nod to the unsavoury acknowledgment that the evil step-parent is not just a character in fairy tales.
Step-parents beat children under five to death at per capita rates more than 120 times higher than do genetic parents, according to an analysis of Canadian homicide data from 1974 to 1990.
And overall, step-parents abuse and kill kids at much higher rates than birth parents. Grim but true, says Martin Daly, an evolutionary psychologist at McMaster University who has researched the nasty subject.
“There are some people who want desperately to say this ain’t so,” he said in a recent interview. “It’s really not disputable. It’s a fact.”
Most step-parents do not abuse their kids, of course, but even step-parents in well-functioning families may not particularly like their stepchildren, says Daly.
The evolutionary rationale behind such indifference is that step-parents simply don’t care as much about kids as biological parents because they’re not passing on their genes to future generations.
“It’s clear that for many people who are in step-parental relations to kids, the kid came along as a piece of excess baggage as far as they’re concerned,” he explains.
“They wanted the parent as a partner and the stepkid comes on as part of the bargain but they never like it and resent it.”
The research also shows that murderous step-parents tend to kill kids in much more brutal ways than biological parents, says Daly.
“A throat-slashing is really off the curve. That one’s super-ugly,” he says of the killing of five-year-old B.C. girl Clare Shelswell in Washington state last Sunday. Her stepfather has been charged with first-degree murder in connection with the case.
“Becoming a step-parent may be a tolerable price to pay for a