Socio-demographic heterogamy is commonly believed to lead to lower relationship stability due to the presence of cultural differences between partners. This explanation lacks empirical support, as psychology studies have not confirmed the link between heterogamy and cultural differences, whereas sociological studies have been characterized by problems related to the choice and measurement of cultural differences. Progressing from previous research, this article examines the specific link between educational heterogamy and cultural differences in the domain of child-rearing. Results partly confirm the alternative hypotheses of child-rearing values and behaviors being subject to gender differences and processes of selection between partners. Nonetheless, they also indicate a positive link between educational heterogamy and differences in child-rearing values and behaviors between partners.