Due to the ageing process, the provision of long-term care (LTC) to the dependent elderly has become a major challenge of our epoch. But at the same time, our societies are characterized, since the 1970s, by a significant postponement of births. This paper aims at examining the impact of those demographic trends on the optimal family policy. We develop a four-period OLG model where individuals, who receive children's informal LTC at the old age, must choose, when being young, how to allocate births along their lifecycle. It is shown that early children provide more LTC to their elderly parents than latechildren, because of the lower opportunity cost of providing LTC when being retired. In comparison with the social optimum, individuals have...