"The Cinderella effect" is a great example of how supporting the traditional family is not the mere result of 'unenlightened', prudish, narrow conservatives. The destruction of the traditional family has real, devastating consequences. Even evolutionary psychologists, with whose root reasoning the typical conservative Christian can hardly be said to be sympathetic, will acknowledge that step-parents are much more likely to abuse their children than natural parents. "Step-parents beat children under five to death at per capita rates more than 120 times higher than do genetic parents..."(Jacobs 2010). Not only are the rates of the murder of one's children much higher among step-parents, but the method of killing the child is notably more extreme(Jacobs 2010). According to evolutionary psychologist Martin Daily, of McMaster Universty,
"There are people who want desperately to say this ain't so...It's really not disputable. It's a fact...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...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."
Evolutionary psychologists believe that the reason for this is that step-parents are less interested in caring for those who do not pass on their genes. Since evolutionary psychologists believe that we are biologically hardwired to engage in activity which is advantageous in passing on our genes, it follows that step-parents would be less interested in investing a great deal of time and energy in child-rearing that has little or no value in propagating their genetic material.
In his book Foundations of Evolutionary Psychology, Daly warns that the step-parent/step-child relationship will be qualitatively different from the relationship between a parent and his or her natural child(Jacobs 2010). This certainly does not, of course, mean that all natural parents will be good parents, or that all step-parents will be bad parents; but it is clear that step-parents will tend to have a relationship with their step-children that is qualitatively different from the relationship of a natural parent to his or her natural child.
Whether or not the formal cause of the qualitative disparity between the relationship step-parents have with their step-children vs. the one parents have their natural children will continue to be a dispute between many conservatives and evolutionary psychologists, but one fact is clear: having a step-parent, on the whole, is qualitatively inferior to having a natural parent.
Jacobs, Mindelle (2010). The Cinderella effect is not just a fairy tale. Retrieved from: http://www.edmontonsun.com/comment/columnists/2010/07/02/14594536.html