The study, published in 2000 and conducted by Temrin and colleagues argued that when Daly and Wilson classified homicides according to family situation, they did not account for the genetic relatedness of the parent who actually committed the crime. Next up was women with no biological children and part-time care of stepkids, and the fourth group was mothers with biological kids as well as part-time responsibility for stepchildren. Find out more about her courses at www.happysteps.co.uk, Becoming a stepmother inspired a psychology lecturer to delve into the dynamic of the stepfamily, The epitome of the wicked stepmother, from the 1950 version of Cinderella. , This article is about parenting.
The normative theory proposes that, due to genetic repercussions, incest among genetically related individuals is a widespread taboo and would thus be less common among biological relatives.  Tooley et al.
In the Swedish sample, in two out of the seven homicides with a genetic and non-genetic parent, the offender was actually the genetic parent and thus these homicides do not support Daly and Wilson's definition of the Cinderella effect. The first category covered mothers with full-time stepkids and full-time care of biological children. , The findings of Daly and Wilson have been called into question by one study of child homicides in Sweden between 1975 and 1995, which found that children living in households with a non-genetic parent were not at an increased risk of homicide when compared to children living with both genetic parents. , Furthermore, a study of parental investment behaviors among American men living in Albuquerque, New Mexico, reveals a trend of increasing financial expenditures on genetic offspring in comparison to step-offspring, which also suggests that parents are less inclined to preserve the well-being of stepchildren. Temrin and colleagues neglect to consider the fact that the proportion of children in living situations with a stepparent is not constant for all child age groups, but rather increases with age.  However, they also note that these traits are simply indicative, and do not inevitably lead to child maltreatment.  Buller also points out that the conclusion that non-biological parents are more likely to abuse children is contradicted by the fact that even if the rate of abuse among stepparents was disproportionate, the lowest rate of child abuse is found among adoptive parents.  This higher risk of injury for stepchildren can be attributed to the fact that stepparents occupy the same supervisory role as a genetic parent, yet they have a lower intrinsic commitment to protecting the child and therefore are less likely to be adequately vigilant.
 The author argues that these results show that in terms of time invested, men favor their children over stepchildren, and this preference is not attributable to the duration of the adult-child relationship, a factor which is sometimes believed to be a confounding variable in the Cinderella effect.