The specter of demographic decline haunted many European nations as they faced mutual competition, growing geopolitical tensions, and dwindling birth rates from the late nineteenth onwards. Amid these developments, the homosexual emerged as a loathsome incarnation of decadence, effeminacy, and infertility, but it did so in some countries more than others. This chapter compares the discourse of demographic decline in France and Belgium. It shows how alarmist declinism was much more pronounced in the former following defeat in the Franco-Prussian War. Belgium, by contrast, was not a major geopolitical power and far less concerned with military and demographic prowess. Moreover, when the birth rate began tapering off there too, the Catholic Church rather than nationalist voices formulated the country’s response. It did so in a vocabulary specifically calibrated to avoid naming sexuality’s supposed ‘aberrations,’ including homosexuality, so as not to let the genie out of the bottle. The latter, these Catholics argued, had been the fatal mistake of countries where a scientific discourse of ‘perversion’ had been allowed to circulate freely, and where ‘perverts’ and ‘inverts’ had now begun using that very scientific vocabulary in their own defense.