Martin Daly and Margo Wilson’s groundbreaking research into the innate risks stepparents present to their stepchildren synthesized the data that we as humans innately know… we like ‘our’ things better and that includes our offspring.
The two Canadian researchers found staggering evidence, not only in the United States but around the world, that
having a stepparent in the household “turned out to be the most powerful epidemiological risk factor for child abuse and child homicide yet known.”
Moreover, they conclude in their influential 2002 paper, The Cinderella Effect: Parental Discrimination Against Stepchildren, that “non-violent discrimination against stepchildren is substantial and ubiquitous.”
The “non-violent discrimination against stepchildren” the researchers noted ran the gamut. It was at times as insignificant as less candy given as a treat or shopping the sales rack at the local department store for their stepchild while buying expensive name brand clothing for their genetically related children to providing less food to the stepchild, less money towards higher education, etc. It showed up as fewer hugs or words of comfort offered to the stepchild. Having the stepchild attend public school when their genetically related children went to private school. It was all related to expending less effort, resources, and time when it came to rearing their stepchild. The differences in treatment may be barely perceptible to an outsider, and perhaps, even the biological parent. However, the differences are real and do exist.
The contrast in genetic versus non-genetic child treatment is easily explained if one views the data with the mindset of an evolutionary psychologist. Humans are not so different than other animals that inhabit this planet. Rare is the animal that willingly undertakes the responsibility of rearing his predecessor’s offspring. This behavior in humans has been attributed more to ‘mating effort’ than altruism. It’s “part of the cost of courting a single parent who, despite the burden of dependent young, remains an attractive prospective mate in a limited mating market.” When viewed as mating effort, it is not surprising that stepparents are willing participants in rearing another’s child. This investment should not be taken to imply that stepparents commonly (or ever) come to feel the sort of commitment ordinarily felt by genetic parents. Rare is the case that a stepchild’s welfare was as valuable as one’s own child’s welfare.
Every culture has its own version of Cinderella and for good reason. Cinderella represents basic ongoing tension in human society. Stepparenting obligations are seldom attractive and dependant children decrease the parent’s ‘value’ in the marriage market. Historically, the issue of stepparenting has been dealt with in a variety of ways. Remarrying parents sometimes left preexisting children with postmenopausal female relatives to rear. Other times, the widow would marry her dead husband’s brother assuming the genetically related uncle would feel some tenderness toward’s his brother’s children. Recently, kids are expected to tag along as well as they can and hope that their welfare will remain a high priority for their remaining genetic parent. Sometimes the genetic parent has to choose between the new mate and the child and may turn a blind eye to the exploitation and abuse of their child.
The study of child maltreatment in step- versus genetic- parent homes was not formally done until 1980 when it was reported that stepchildren constituted a much higher proportion of the U.S. child abuse cases than their numbers in the population would warrant.
It was found that young children incurred about seven times higher rates of physical abuse in step- versus genetic- parent homes than in two-genetic-parent homes, the differential in fatal abuse was on the order of 100 fold.
Genetic parents kill their children as well, but recent studies indicate that the motives in these cases tend to be different. Where filicidal parents are often deeply depressed and may think of murder-suicide as an act of benevolence, homicidal stepparents are seldom suicidal and usually manifest their disdain to their victims in the brutality of their lethal acts. (Daly and Wilson, 1994)
The groundbreaking studies by Daly and Wilson present an uncomfortable reality. Raising a human from infancy to adulthood and beyond is a costly endeavor. Humans are designed to be discriminative about efforts put forth to nourish, support, and protect. They found the most plausible interpretation of the high prevalence of stepchildren among abuse victims is simply that stepparents love the children in their care less, and resent them more, on average, than genetic parents.
Successful relationships with a spouse, friend, coworker, or even a sibling typically involve reciprocity. If one person continually takes without giving, the relationship sours. In contrast, parent-offspring relations are unique. The flow of resources is very onesided and parents derive joy, rather than resentment, from the exploitive nature of that relationship.
Daly and Wilson did not want to give the impression that successful stepparenting is an impossible dream, as most relationships work reasonably well. It is foolhardy to believe that stepparents often come to feel the selfless commitment that is so common in genetic parents. They don’t. It isn’t difficult to understand that parental love is special and seldom fully activated in stepparents.
Common wisdom has been substantiated by peer-reviewed research. Parents love their children. This love is profound and not readily substitutable. The notion that stepparenthood is psychologically equivalent to genetic parenthood and that ‘bonding’ experience is sufficient to evoke the full depth of parental feeling is to misunderstand the complexity of human nature.