The Marshall Islands, Micronesia, Nauru, Palau, Papua New Guinea, Suriname, Tonga, and the United States of America—what do these eight countries have in common? These are the only countries in the world without paid parental leave. You may not have expected to see the United States on such a list, given that the country has the world’s highest GDP and a generally high interest in human rights. How did it develop into a nation so “unfriendly” to parents?

Before focusing on the U.S., let us first consider the global history of parental (specifically, maternity) leave. The issue of childbearing, as it applied to women in the modern workplace, first came into focus during World War I. With so many men sent off to the front, women were the ones who worked in weapons and ammunitions factories or provided nursing care in field hospitals, clearly demonstrating the value of their labor. Accordingly, mechanisms to mobilize women with infants—such as designating places and times for breastfeeding at work—were introduced in Europe. Once the war ended in 1918, however, society reversed course: the returning soldiers needed jobs back home, and the women who had held those jobs during the war suddenly found themselves unwelcome in the workforce. In fact, the International Labor Organization (ILO), which had been founded as a sister organization of the League of Nations in 1919, did not allow women to vote in its first meeting that October. But women, now aware of the power of their labor and their rights, stood up boldly against their exclusion. Women’s unions and activists in the United States called on women around the world to attend a working women’s international conference in Washington. (One prominent Japanese participant was Takako Tanaka, who traveled all the way to the U.S. while four months pregnant to attend. An advocate for women and workers in Japan and abroad, she had studied at Stanford University and the University of Chicago, had a master’s degree in sociology, and was the niece of Eiichi Shibusawa, a distinguished businessman known as the father of Japanese capitalism.) Together, the efforts of these women succeeded in pushing the initially reluctant ILO to adopt the “Convention concerning the Employment of Women before and after Childbirth,” also known as the Maternity Protection Convention, 1919. This marked the first time the concept of paid maternity leave (for a total of 12 weeks before and after childbirth) was officially recommended for implementation.

Maternity leave systems would go on to be introduced across Europe, Central and South America, and Asia after World War II. European countries in particular were invested in ensuring women could both work outside the home and have children. Their lands had been used as battlefields, where many men had lost their lives, and their economies were exhausted. Women, then, represented a solution: their labor could rekindle the economy, and their ability to bear children could compensate for the decline in population. Against this economic backdrop, measures to encourage women to participate in the workforce while also having and raising children were established and promoted across the continent.

The United States, on the other hand, had not suffered nearly as much damage to its economy or labor force. Contrary to their European counterparts, American women were encouraged to stay home to have and raise their children in order to free up jobs for returning soldiers. Later on, more and more women began to participate in the workforce alongside their male peers, but even so, discussions on maternity leave did not progress. There are several possible factors behind this. First, the idea that maternity leave is not a right, but rather a luxury or privilege, was deeply entrenched. In the U.S., where people tend to value the individual and rely on themselves, there is already strong resistance to increasing taxation of individuals and governmental provision of social welfare. During the Cold War, tensions with the Soviet Union also meant that any such policy could invoke the specter of socialism, amplifying resistance. Another potential factor lies in the assumption, though false, that social welfare beneficiaries are concentrated among the Black community and other people of color, which may have given rise to opposition to implementing a nationwide maternity leave policy. Immigration is yet another factor: The American population is continuously shored up by the stream of immigrants, whether documented or undocumented, coming into the country through the 1,951-mile land border with Mexico. Thus, unlike countries facing a shrinking population and falling birthrate, the U.S. has no particular impetus to implement a parental leave policy as a population-boosting measure.