Where’s your birth certificate? It’s likely stashed in a filing cabinet along with other essential documents or tucked in a safety deposit box, a testament to the significance of what might otherwise be mistaken for a simple piece of paper. But people didn’t always need birth certificates, or even a record of their own birth—and the history of birth certificates is much shorter than you might think.

For centuries, births and deaths were documented in church records, not government ones. And early attempts in America to get the government involved in recording births stalled. In 1632, Virginia’s General Assembly passed a law that required all ministers to keep track of christenings, marriages and burials, but the practice died almost immediately because it was so foreign to church officials. Massachusetts passed a 1639 law requiring towns to do the same thing, but records remained patchy and inaccurate.

Part of the reason was the messy process of childbirth itself: Women birthed children at home or in friends’ houses, and many did not survive infancy or childhood. If a child did not live to be baptized, was enslaved or moved from place to place, its birth might not be recorded at all—or its memory might live on only in a family Bible or its mother’s memory.

But during the Progressive Era, reformers decided it was time for a change. Their interest in all kinds of data—especially facts and figures about births and deaths—arose during the height of European immigration to the United States. Thirty million Europeans poured into the country between 1815 and 1915, and urban areas struggled to keep up with the influx. They crowded into tenements and poor neighborhoods, straining the few resources cities had.

Reformers, many of them affluent women, set to work tackling the “immigrant problem.” They hoped that by counting and characterizing the people who lived in cities, they could illustrate the extent of the problem and figure out ways to tackle it. Statistics, they thought, could also illustrate more modern ways to solve public health problems and optimize city life.

And so the Progressive craze for counting began. Reformers made maps of ethnicities and lists of the unemployed. But when it came to public health, they lacked data. They began to pressure the U.S. Bureau of the Census to register all births.

The Bureau began to roll out standardized birth certificates in different areas of the country, and states gradually adopted them, but early birth certificates didn’t look like they do now. They captured only a brief outline of the child’s identity and its parents. And since hospital deliveries were not yet common, the system still missed a large percentage of people born at home.

It also failed to do away with a worrisome problem: the risk of a child being switched or lost track of after birth. Early maternity wards did not have stringent identification policies. As historian Judith Walzer Leavitt writes, mothers worried they would go home with the wrong baby—and sometimes they did.

It took a world war to finally give birth certificates the push they needed to become universal. During World War II, defense-related plants began to hire in unprecedented numbers—but by law, they could only hire American citizens. This created a crisis for the estimated 43 million native-born Americans—nearly one third of the country—who couldn’t prove when—and where—they were born. At the time, the article estimated, 200,000 people were born every year without getting a birth certificate.

Magazines and newspapers began to try to educate people on the need for birth certificates—but warned of the difficulty of getting one during wartime. “A birth certificate is a good thing to have,” explained a 1942 article in Good Housekeeping. “Please do not apply for a birth certificate today unless you absolutely must have one.”

The normalization of the birth certificate process, however, was not without its societal difficulties. As the New Republic’s Liza Mundy explains, the national system of issuing two birth certificates for adopted children—one listing their birth parents, one listing their adoptive parents—then sealing the original birth certificate, made the system “party to one of our culture’s biggest collective lies.” Adoptive parents could pretend adoptive families were biological ones—and today, children must still petition for their own original birth certificates and adoptive records in many states.

As the social welfare state expanded, so did the need for birth certificates. In 1946, the National Office of Vital Statistics took over birth certificates nationally. These days, they prove eligibility for things like Social Security, Medicaid, and public programs like WIC (offering food and nutrition to women, mothers and young children) that might make a Progressive-Era reformer proud.