Sermonizer children, Head of family's teenagers, the advertisement products regularly failing adults and by that a weak transmission. The “kidult” together with the adult childish, the one of the “juvenile senior” or also the one of “tweens” which call for the redefinition of the childhood outlines, are all indicators of a muddle of ages, of life cycle and of the implementing generation in our contemporary societies and which the advertising exploites with pleasure. They question a society soaked of cult of youth, nostalgic and depressed. In this contribution, we concentrate on the way the advertisement in the years 2000, by the mean of classical models of generational differentiation and other more contemporary, plays with this confusion of borders and participates to the social construction of life ages.