New Study: Motherhood Alone Explains Gender Wage Gap, Not Discrimination
A groundbreaking new economic study has reignited the debate about the persistent wage gap between men and women, providing compelling evidence that motherhood—not gender discrimination—is the primary driver of this economic disparity. The research, conducted by Camille Landais of the London School of Economics and colleagues, offers what may be the most definitive natural experiment yet on this contentious issue.
The Science Fiction Premise and Economic Reality
Ursula K. Le Guin's classic science-fiction novel "The Left Hand of Darkness" imagined a planet called Winter where all people are "ambisexual," developing temporary sexual characteristics each month. This thought experiment raises profound questions about gender roles and economic outcomes. If anyone could potentially become pregnant, would wage disparities based on gender still exist? The new research suggests they would not.
For decades, economists have debated why men consistently earn more than women. Claudia Goldin of Harvard University, who won the Nobel Prize in Economics in 2023, argued that motherhood explains essentially all of the wage gap. Her work seemed to settle the debate, but recent studies using novel datasets have prompted renewed examination of this conclusion.
The Scandinavian Data Revolution
Over the past two years, economists have gained access to powerful new datasets from Scandinavian countries that match detailed health records with comprehensive income data. This has allowed researchers to conduct sophisticated natural experiments by examining variations in women's fertility.
Previous studies looked at women undergoing in vitro fertilization (IVF) treatment—women who clearly wanted children—and compared the long-term earnings of those who became pregnant versus those who did not. Initially, the mothers earned significantly less, but this gap gradually shrank over time. Remarkably, 10-15 years after childbirth, mothers even earned a small premium compared to their childless counterparts.
The MRKH Syndrome Study: A Natural Experiment
The latest research takes this methodology further by examining women with Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, a rare condition in which girls are born without a uterus but otherwise develop normally. These women know from early adolescence that they will never bear children, unlike women who discover infertility later in life after attempting to conceive naturally or through IVF.
This distinction is crucial because women who anticipate motherhood may make different investments in their human capital. They might pursue less education, choose different career paths, or make other decisions based on the expectation that they will need to step back from their careers after giving birth.
The findings are striking:- Women with MRKH syndrome earn approximately the same as other women and men during early adulthood
- In their 30s and 40s, when the typical gender wage gap emerges, women with MRKH follow a completely different trajectory
- Their wage progression is almost identical to that of their male peers
Essentially, when both motherhood and the anticipation of motherhood are removed from the equation, the wage gap between men and women disappears entirely.
Implications for Workplace Policy and Gender Equality
This research represents what may be the most effective way yet to isolate the effects of childbearing from other female characteristics and study their impact on earnings. The findings suggest that workplace policies should focus more on supporting parents—particularly mothers—rather than addressing presumed gender discrimination.
The study challenges conventional wisdom about gender discrimination in the workplace while highlighting the significant economic costs associated with childbearing and childrearing. It suggests that the solution to the gender wage gap lies not in combating workplace bias, but in creating better support systems for parents, including more flexible work arrangements, better parental leave policies, and affordable childcare options.
As the researchers note, this natural experiment provides insights that would be difficult to obtain any other way. While we may not live on Ursula K. Le Guin's fictional planet Winter, this research brings us closer to understanding how childbearing shapes economic outcomes in our own world.
