The Baby Boom was undoubtedly one of the more emblematic events of the twentieth century. As it was a distinctly demographic phenomenon, it has been dissected by some of the most distinguished of demographers. Yet its greatest influence is not in demography, but in fields like marketing, pop-psychology, and even gerontology: the Baby-Boomers rather than the generation currently at reproductive ages are blamed for structural ageing. This paper questions aspects of Baby-Boom mythology. It asks how it has been measured: a 'boom' suggests numerical volume, yet instead we measure flows. It questions whether the hegemonic model of the boom -the American one that has effectively delineated its parameters in Europe, Australasia and Japan, both among demographers and in the popular media -really does apply to other countries. It also asks whether or not Western Europe's limited surges in births really qualify as booms in the strict sense of the term. Finally, it raises questions more in the field of the sociology of knowledge: the way the Baby Boom mythology has spread often in the face of counterfactual evidence. This paper is a revised version of the Australian Population Association's 2006 Borrie Lecture.