Julius Ilciukas

I study how parenthood affects women’s labor market outcomes and gender inequality, using quasi-experimental variation in the success of assisted conception procedures. To account for births following an initially failed procedure, I develop a method to quantify treatment effects in quasi-experimental settings with dynamic non-compliance, where individuals may opt to undergo assignment multiple times. Using administrative data from the Netherlands, I find that parenthood persistently reduces women’s work hours and income by 9 to 27 percent. Despite these substantial effects, I find that at least half of the observed within-couple gender inequality in these outcomes after childbirth cannot be attributed to parenthood. I propose a unified framework to disentangle and quantify the bias in conventional estimators arising from selective parenthood timing and timing-dependent effects, demonstrating that these factors are the key to reconciling conflicting findings in the literature.

We estimate the impact of having siblings on school outcomes of first-born children. By leveraging exogenous variation in first and later IVF treatments, we construct an improved instrumental variable estimator that tackles exclusion violations and identifies causal effects for compliers and always takers with siblings from later treatments. With nationwide school surveys linked to administrative records, we find that first-born children with and without siblings perform equally well on nationwide reading and math tests, are equally conscientious, agreeable, and emotionally stable, and report the same levels of school well-being. We conclude that the cognitive and non-cognitive outcomes of school-aged first-born children neither benefit nor suffer much from having siblings.

I study how reduced retirement opportunities in one generation affect fertility in the subsequent generation. I use administrative Dutch data and exploit the 2006 Dutch pension reform, which induced individuals born from January 1, 1950 onward to delay retirement while exempting those born earlier. I find that this reform reduced fertility among women with affected mothers. The reduction is economically significant and persists after the impact on retirement fades out. I supplement my analysis with survey evidence and argue that the fertility reduction can be explained by reduced grandparental child care supply.