The paper uses an OLG model to study the interaction between policies designed to ensure the sustainability of the pension system, i.e. child allowances and pensions policies, and grandparental childcare. We find that the rise in grandparenting negatively affects the elderly labour supply hampering the impact of pension policies designed to raise the retirement age and lengthen working lives. Then, we introduce child allowances and find that the impact of child allowances on the fertility rate is influenced by the efficiency of grandparenting in reducing child-rearing costs. Child benefits have a positive impact on fertility only if grandparenting is not very effective at reducing childcare costs. This suggests that the role of grandparents in various countries may partly explain the inconsistency in empirical evidence on the relationship between child benefits and fertility rates. The study also finds that child benefits have a positive impact on the elderly labour supply when grandparenting is efficient.

本文使用OLG模型来研究旨在确保养老金制度可持续性的政策（即儿童津贴和养老金政策）与祖父母儿童保育之间的相互作用。我们发现，祖父母人数的增加对老年人劳动力供应产生了负面影响，阻碍了旨在提高退休年龄和延长工作寿命的养老金政策的影响。然后，我们引入了子女津贴，发现子女津贴对生育率的影响受到祖父母养育成本降低效率的影响。只有当祖父母在降低儿童保育成本方面不是很有效时，儿童福利才会对生育率产生积极影响。这表明祖父母在不同国家的作用可能部分解释了儿童福利与生育率之间关系的经验证据的不一致。研究还发现，当祖父母高效时，儿童福利对老年人劳动力供给产生积极影响。