This paper explores how the parenthood wage penalty is partially explained by an increased within-couple gap in job uniqueness (i.e., the within-establishment substitutability of workers). Uniqueness is rewarded with higher wages, but it requires worker presenteeism (i.e., the lack of unpredictable work absences), which entails a higher cost of childbearing. Using a within-couple event study approach, we show that after the arrival of the first child, women take more days of absence than men and their likelihood of holding jobs with low substitutability decreases. We find that 15 years after childbearing, the male-female gender gap in holding a (higher-paying) unique jobs increases by 6 percentage points. The results suggest that structural changes towards greater work flexibility, making it less costly for workers in unique jobs not to be present, can help to reduce the parenthood wage penalty.

---

1 January 2026

---

Journal of Human Resources 60(4) , pp.1435-1457, 2026

---

DOI: 10.3368/jhr.1121-12014R2

https://jhr.uwpress.org/content/early/2022/11/01/jhr.1121-12014R2

This Journal article is published under the centre's Labour programme.

This publication comes under the following theme: Gender in the labour market