You had to get a blood test to get married because, starting in the 1930s, states turned the marriage license counter into a screening checkpoint for syphilis — a disease that at the time infected roughly one in ten Americans and could devastate a spouse or an unborn child. Every state eventually repealed the requirement as infection rates fell and the tests stopped catching enough cases to justify the cost. Montana was the last to drop it, in 2019.
The Syphilis Crisis Behind the Law
In the early 1930s, Public Health Service surveys estimated that about 10 percent of Americans were infected with syphilis, and roughly 60,000 children were born each year with the congenital form.1National Center for Biotechnology Information (NCBI) / PMC. A 20th Century Historical Perspective on Congenital Syphilis and Lessons for Today Syphilis caused twice as many infections annually as tuberculosis and was blamed for an estimated 18 percent of all deaths from organic heart disease. Untreated, it could progress to blindness, paralysis, and severe mental illness. A pregnant person with the infection could pass it to the child, causing stillbirth, deformity, or lifelong health problems.
In 1936, Surgeon General Thomas Parran launched a national campaign to identify and treat syphilis on a massive scale. His strategy combined free diagnostic centers, contact tracing, public education, and mandatory testing during pregnancy and before marriage. The campaign deliberately framed syphilis as an ordinary infectious disease that could strike anyone, breaking from earlier approaches that had treated it as a moral failing confined to marginalized groups.
Connecticut had already set the template a year earlier. In 1935, the state passed what became known as the “premarital examination law,” requiring both a blood test for syphilis and a physical examination before a marriage license could be issued. Other states followed quickly. By 1944, thirty states had enacted similar mandates. Within another decade, forty of the then-forty-eight states required premarital blood tests.2CDC Stacks. Premarital Health Examination Legislation
What the Test Actually Screened For
Syphilis was the main target. The standard screening tool was the Wassermann test, developed in 1906 by German bacteriologist August von Wassermann. It detected antibodies produced in response to syphilis infection, though it was not perfectly accurate. False positives were a known problem, and better tests eventually replaced it.
Some states expanded their screening. A handful required testing for rubella, which can cause severe birth defects if contracted during pregnancy. A few added gonorrhea screening. But syphilis was the universal target in every state that mandated premarital blood work.
The Eugenic Roots of Premarital Examination
The syphilis framing was not where these laws started. Historians have traced the earliest premarital examination statutes to the eugenics movement of the early twentieth century. Wisconsin passed the first such law in 1913, and its stated goals went beyond disease control: proponents wanted to prevent people deemed “unfit” from reproducing. Over time the explicit eugenic rationale faded from public discussion, replaced by the more palatable public health framing of disease screening. The legal infrastructure those early advocates built, though, became the foundation for the syphilis-testing mandates that spread nationwide in the 1930s and 1940s.
The Short-Lived HIV Testing Revival
When the AIDS crisis hit in the 1980s, some lawmakers saw premarital blood tests as a ready-made framework for a new disease. Illinois went furthest, enacting mandatory premarital HIV testing in 1988. Louisiana briefly passed a similar law before repealing it that same year.3Open Scholarship: Washington University School of Law. For Better or for Worse? Mandatory AIDS Testing for Marriage License Applicants
The Illinois program became a cautionary tale. It cost an estimated $5.6 million per year. After roughly a year, it had screened about 250,000 people and identified only 52 who tested positive for HIV. Illinois also saw a measurable drop in marriage license applications, because couples were crossing into neighboring states like Indiana and Wisconsin to avoid the test. Governor James Thompson signed the repeal in September 1989, barely a year and a half after the law took effect.3Open Scholarship: Washington University School of Law. For Better or for Worse? Mandatory AIDS Testing for Marriage License Applicants That failure effectively killed any remaining political appetite for tying disease screening to marriage licenses.
Why Every State Eventually Repealed the Requirement
The repeal wave started in the 1980s and stretched over three decades. The driver was a simple cost-benefit problem: the tests caught almost nobody. Penicillin had been proven effective against syphilis by 1943, and widespread treatment drove infection rates down sharply in the decades that followed. By the time states began reconsidering their laws, mandatory premarital screening was spending enormous sums to find vanishingly few cases. One widely cited estimate found that couples nationwide were spending over $80 million on premarital syphilis tests that identified only 456 positive cases.
The timeline tells the story. As of 1980, thirty-four states still had blood test requirements on the books. Nineteen repealed during the 1980s, seven more in the 1990s, and another seven between 2000 and 2008. Mississippi dropped its requirement in 2012. Montana held on the longest. It was the last state in the country still requiring the test when its legislature passed HB 136 in 2019, abolishing the premarital blood test for women.4Montana State Legislature. HB 136 – An Act Abolishing the Premarital Blood Test for Women
The reasoning behind the repeals was straightforward. Modern STI testing is widely available through doctors’ offices, clinics, and public health departments. Tying it to marriage licenses made some sense in the 1930s, when most people had limited contact with the healthcare system and syphilis was rampant. By the late twentieth century, the marriage-license checkpoint was adding cost and delay without meaningfully improving public health.
No State Requires a Blood Test Today
If you are applying for a marriage license now, no state will ask you for a blood test. The requirement is gone across the country. What a clerk’s office typically asks for instead is photo identification, proof of how any prior marriage ended, your Social Security number, and the license fee. None of that is health screening. The health rationale that built these laws nearly a century ago has not survived the collapse of syphilis as a mass epidemic or the rise of ordinary medical testing outside the courthouse.