In many societies, girls are more often killed by their parents than boys. However, not much of this is known in contemporary societies. This study had two main objectives. The first was to assess whether the number of boy and girl victims of maternal filicide differ in the literature from 1959 to 2000. Using two scientific databases, Medline and PsycINFO, 20 texts were pertinent. The second objective was to identify the variables that differentiate the mothers who killed a son and those who killed a daughter in a sample of 42 women from the province of Quebec (Canada). Analysis of the data for the first part indicate that the numbers of sons and daughters killed by their mothers are similar in the literature. For the second aim no significant differences were noted between the women who killed a son and those who killed a daughter for 30 variables studied, e.g., motivation, method of killing, age of the victims, etc.