“Die Fruchtbarkeit in Mischehen,” Zeitschrift für Demographie und Statistik der Juden 4, no. 11 (1908): 175–76.
This brief piece appears anonymously, but the author is most likely Arthur Ruppin. A significant number of short pieces appeared without attribution in this journal. Ruppin, its editor, noted in his diary that he or his assistant, Jakob Thon, wrote all the unattributed pieces. For biographical information on Ruppin, see the headnote for selection 5.
In an article by Wieth-Knudsen (“Racial Crossing and Fertility”) in the Political-Anthropological Review (vol. 7, no. 6), we learn that the statistics on fertility in marriages in Prussia for the years 1875–1900 yield the following picture:
Pure Marriages (Reine Ehen):
Catholic marriages: 5 children
Protestant marriages: 4 children
Jewish marriages: 3.8 children
Mixed Marriages:
Protestant-Catholic marriages: 3.1 children
Christian-Jewish marriages: 1.7 children
In 1895 in Prussia, 21 percent of all Protestant-Catholic marriages were childless, and 35 percent of all Christian-Jewish marriages were childless.
Wieth-Knudsen traces, via de Lapouge (Théorie d’infécondité par défaut d’accomodation résispropue), the lower fertility of Christian-Jewish marriages back to racial difference, and chiefly to psychological factors connected to this difference. The author [Wieth-Knudsen] is of the opinion that in mixed marriages the psychological unity or homogeneity is lacking, and that the sense of family, the joy taken in numerous offspring, is weakened or debilitated. The lower fertility rates among Christian-Jewish married couples cannot be explained by differences in age or standards of living, since such conditions are hardly any different when it comes to Protestant-Catholic intermarriages and to pure Jewish marriages—although the latter always have the disadvantage when it comes to fertility.