We study how delayed retirement and higher fertility can improve pension sustainability in the near and long term. We provide a unified heterogeneous-agent overlapping-generations framework to study general-equilibrium transitions under these policies and compare their effects on fiscal sustainability and welfare across cohorts. In an application to China, delayed retirement provides immediate fiscal relief but has a limited long-run effect. Higher fertility substantially reduces long-run pension deficits, but only after a lag of about two decades. Combining the two provides complementary relief, easing fiscal pressure on the pension system throughout the transition. We construct the fiscal value of birth as a break-even benchmark for governments to assess pro-natalist subsidies. Using China as an example, we find that raising the total fertility rate from 1.0 to 1.3–1.5 generates average present-value fiscal relief of approximately 125,000–132,000 yuan per additional birth.