In this article I argue that the non-reciprocity problem does not apply to intergenerational justice. Future generations impact, here and now, on the well-being of people now living. I firstly illustrate the economic-synchronic model of direct intergenerational reciprocity (DIR): future generations allow people now living to maintain the economic system future-oriented and capital-preserving. The rational choice for people now living is to guarantee transgenerational sufficiency to future generations. I then analyse the axiological-synchronic model of DIR: future generations give meaning and (...) value to many of the activities that people now living carry out, and this is a compelling reason for the latter to worry about the former. I argue that only the economic-synchronic model of DIR can consistently explain why we need future generations. I conclude by discussing the limits of indirect intergenerational reciprocity. (shrink)