A recent controversy over birth certificates in Arkansas demonstrates that these slips of paper are imbued with political and social meaning. In 2015, a married couple, Marisa and Terrah Pavan, had their first child, who was conceived through sperm donation. The Arkansas Department of Health, or ADH, listed only Terrah, who gave birth to their daughter, on the baby’s birth certificate. This was contrary to state law, under which the spouse of the birth mother also is automatically listed.

The case went to the Supreme Court, which ruled that same-sex couples must receive the same legal treatment as different-sex ones. When an Arkansas circuit-court judge later ruled that the ADH must comply, this triggered a brief crisis Friday. Until the state ended its practice, now considered discriminatory, no newborns were allowed to be issued birth certificates. The governor ordered the ADH to meet the Supreme Court standard. After a few hours, the agency relented. Both Pavans can now finally be named on their child’s birth certificate.

This may have been a blink-and-you-might-miss-it news story for many outside Arkansas. But it’s only the latest example in a long history of using birth certificates to make governmental and social statements about identity and relationships.

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Birth registration has long been useful to governments, allowing them to tax, conscript, and count the population. That effort was traditionally the purview of churches, where the practice dates to the 16th century. It wasn’t until 1837, in England and Wales, that birth registration began to become standardized and subject to governmental control.* Several decades later, it was mandatory to register all births in the two countries.

Today, most countries require birth certificates to be issued within a certain period after birth. The UN Convention on the Rights of the Child also enshrines the right for all children to have their births registered.

For that reason, the birth certificate becomes the first object most people own. Bound up in official identity and personal relationships, its stakes are high. Doubting the accuracy or provenance of a birth certificate can cause shock waves that ripple out to years or even decades later. The “birther” conspiracy during Barack Obama’s first presidential candidacy is a notable example. Donald Trump and others claimed that Barack Obama hadn’t been born in the United States and thus was ineligible for the presidency. The birth certificate is a battleground for debates about parentage, gender, identity, and governmental responsibility.

For those living in countries where birth certificates are rarely seen, it might seem like the document is a relic of an earlier time more obsessed with filial legitimacy. But birth certificates are still essential to basic citizenship rights across the world. For one thing, they often serve as a stepping stone to other identification documents, such as social-security cards and passports.

Elsewhere, the document has more diverse purposes. In Sudan, a birth certificate has to be presented before a child can enroll in school. In the United States, birth certificates are required to register with Native American tribes. In Sri Lanka, a birth certificate makes it possible to respect a minimum age of criminal responsibility; without it, police may informally estimate (and possibly exaggerate) children’s ages. In the United Kingdom, birth certificates help establish eligibility to join the armed forces.

But it’s not always easy to find the document. That situation is especially acute for displaced people. Birth certificates are important for family reunification. Children born in refugee camps face the prospect of becoming stateless if they can’t prove their parentage, and thus where they can claim nationality. This is tricky for Syrians in Turkey, for instance, as Syrian citizenship passes down through the father, and details of the father aren’t always known.

Worldwide, almost a third of all births aren’t registered. Nationally, registration rates vary widely, from 3 percent in Somalia to 100 percent in Bhutan. In some cases, that’s because birth certificates don’t seem useful to parents. For someone who lives in a remote part of a country that doesn’t provide any obvious citizenship benefits, there’s not much of an incentive to bother with registering a child.

There are also practical barriers. Many countries lack the technology or capacity to register each birth, even if doing so is mandated by law. And some countries only register babies born to married parents. Even if they want to register, some parents might not be able to if they cannot afford to travel to a location where births are registered or if they cannot cover the cost of issuing the certificate itself. There are also concerns that governments will misuse registration records eventually, whether for prejudicial policy, compulsory military service, or even ethnic cleansing. In the Soviet Union, “Jewish” was one of the 69 nationality options on birth certificates. Designating Soviet citizens as Jewish enabled discrimination against them, such as by limiting which colleges they could attend.

Some logistical hurdles have been tackled with more funding and resources to vital registration systems, or by making registration more convenient for parents. For instance, Tanzanian parents can register their children via text message, and mobile clinics in Indonesian villages bring birth certificates to new parents. The governance and trust issues, however, are more challenging to address.

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Sometimes the state sees, and documents, its citizens differently than how they see themselves. Gender identity is one such area. In some places, transgender advocates have come under fire for proposals to make gender markers and names optional or amendable on birth certificates.

Overall, legal changes relating to birth certificates show how quickly the law is catching up to social attitudes about sex and gender. In the early 2000s, intersex individuals in Australia sought and received replacement birth certificates that left gender unspecified. But these documents were issued on an ad-hoc, retroactive basis. Later laws, such as one passed in Germany in 2013, officially allowed parents to leave the gender box on birth certificates blank.

In the Philippines, the gender on a birth certificate can be changed in the case of “a clerical or typographical error.” A hard-won legal precedent for changing the gender designation for identity reasons also exists. In a 2008 ruling of the Supreme Court of the Philippines, Jennifer Cagandahan obtained the right to change the name and gender on her birth certificate.

But these examples are outliers. In some places, gender markers on birth certificates can only be changed following gender-reassignment surgery. In many others, even that option is disallowed. This creates a situation where an adult whose gender identity isn’t reflected on their birth certificate might also be stuck with their birth-certificate gender on all the other official identity markers that are derived from it, such as ID cards and passports.

Other types of identity point out how arbitrary certain labels and designations are. One of these is race, which is marked on some birth certificates. Vivian Morris was born in 1969 in Montgomery, Alabama—the town where Rosa Parks famously refused to move to the back of the bus. On Morris’s birth certificate, her Korean mother was listed as white. At the time, there weren’t standard racial categories to choose from, and registration officials had more say. Morris tells me, “I always assumed that she was lumped in with white in Alabama, versus black, because those were the only recognized races back then in the Deep South.” Her experience exposes the gaps between bureaucratic permissibility and the complexity of racial identity. Those gaps haven’t fully closed since Morris’s childhood either: Some U.S. states still don’t allow multiracial children to be marked as such on their birth certificates.

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Also contested are attempts to reflect changing notions of family headship on birth certificates. Japan’s koseki system, which oversees birth, death, and marriage registration, requires all members of a family to bear the same surname. In practice, this system prevents women from retaining their own last names. Around the world, some people whose last names are different to their children’s travel with birth certificates to prove their relationship.

Birth certificates also demonstrate the prevalence of female-headed households. In Jamaica, the father’s name is not listed on a third of birth certificates. In Kenya, until fairly recently, it was customary to write “XXXX” in place of the father’s name for children born to unmarried parents. The term “legitimate” was finally removed from American birth certificates in 1979.

Sometimes birth certificates bear witness to confused conceptions of parentage and legitimacy. England and Wales, for instance, have a dizzying set of rules about when the surname can be changed on the birth certificate, related to parental marriage status, who was present at registration, and what surname the child takes. However, in recognition of same-sex relationships, a U.K. birth certificate can list two mothers and no father. A birth certificate in Argentina can now list two mothers and a father.

These documents also show the extent of progress when it comes to gender relations. Just a few decades ago, U.S. birth certificates listed the father’s occupation but not the mother’s. There was no expectation of working women, at least officially.

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Gender, race, and even date of birth aren’t the only areas where identity, as officially stated on a birth certificate, has been shown to be mutable. Following adoption, birth parents’ names on U.S. birth certificates may be replaced with adoptive parents’ names.

This happened to Rachel Zients Schinderman, whose father died when she was four. As an adult she was adopted by her stepfather, which triggered the reissue of her birth certificate to replace her father’s name with her stepfather’s. This was an emotional experience for Schinderman. “No one could take my real father away from me, and someone else wanted to be there for me too,” she tells me. Even so, the result strikes her as uncanny. “It is very strange to see [my stepfather’s] name there and the age he would have been at the time of my birth.” Schinderman understands why birth certificates get reissued upon adoption, but feels alienated by the bureaucratic requirement for such a change. “I just wish I had the option,” she says.

Schinderman isn’t alone in wanting this choice. There are fierce debates in adoption and genealogy circles over the sealing of original birth certificates when amended birth certificates are generated. Some argue that adoptees deserve to have access to their original documents, and that these should remain immutable records of biological parentage. Others point to the need for privacy for birth parents and respect for adoptive parents.

The legal skirmishes over who should be able to see a birth certificate, and what information it should contain, seem likely to amplify rather than diminish. As technology improves and legal frameworks for parenting continue to evolve, new controversies are bound to play out over birth certificates new and old. Will sperm donors, egg donors, surrogates, and others be reflected? Will these documents allow for more than three people to be named as parents? Will increasingly sophisticated biometrics be embedded into them?

Whatever the future holds for birth certificates, it’s clear that they’ll continue to matter not just for administrative purposes, but for emotional reasons, too. As Schinderman puts it, “even though the birth certificate is just a piece of paper, it is my piece of paper.”

* This article previously misstated the year that birth registration was standardized in England and Wales. We regret the error.