Blood tests were required before marriage mainly to screen couples for syphilis, catch infections before a spouse or future child could be exposed, and route infected applicants into treatment before the wedding. That is the short answer to why blood tests were required before marriage. The laws spread across almost every state between the 1930s and 1950s, lost their medical rationale once penicillin made syphilis easily curable, and were repealed one by one until the last requirement fell in 2019.
The Disease the Laws Were Built to Stop
Syphilis was one of the most feared infections in pre-antibiotic America. Public Health Service surveys in the early 1930s estimated that about 10% of the population was infected, and roughly 60,000 children were born each year with congenital syphilis. A baby born infected could suffer bone deformities, deafness, neurological damage, or death. A 1914 study of 10,000 consecutive births found syphilis was the single most common cause of infant death in the country and concluded that 40% of those deaths were preventable with prenatal screening.1National Library of Medicine. A 20th Century Historical Perspective on Congenital Syphilis
The reasoning behind premarital testing was straightforward. If an infected applicant could be identified and treated before the marriage, the infection would never reach the spouse or any future child. The Wassermann blood test, developed in 1906, made mass screening practical for the first time. It was cheap enough for a government program and reliable enough to catch most active cases.
How the Requirement Spread Across the States
The push for mandatory premarital testing gained momentum under Surgeon General Thomas Parran, who took office in 1936 and treated syphilis eradication as a national priority. Parran reframed the disease as an ordinary public health problem on par with tuberculosis rather than a moral failing, which made legislation politically possible. In 1938, Congress unanimously passed the National Venereal Disease Control Act, funding anti-syphilis programs nationwide.
Connecticut passed the first model premarital examination law in 1935, requiring both parties to undergo a syphilis blood test before receiving a marriage license.2Connecticut General Assembly. Blood Tests for Marriage Licenses Thirty states had similar requirements by 1944, and by the late 1950s the count reached 40 out of 48.3CDC Stacks. Premarital Health Examination Legislation Gallup polling through the 1930s and 1940s showed large majorities of Americans in favor, and the premarital blood test became the first mass blood screening most people ever experienced.
The Eugenics Thread
The public health case was real, but it was not the only motive. Early premarital examination statutes passed between 1913 and 1935 were also promoted by the eugenics movement, which wanted to prevent people deemed “unfit” from marrying and reproducing. A 1913 Wisconsin law, upheld by the state supreme court, opened the door for other states to regulate marriage on eugenic grounds.4National Library of Medicine. Venereal Disease and the Eugenic Marriage Laws, 1913-1935 That second rationale pushed some statutes further than the medical evidence alone would have supported.
Why the Rationale Collapsed
The laws lost their footing slowly, as the numbers kept failing to justify the cost. In New York City’s first year of premarital syphilis testing, only 1.34% of applicants tested positive. Nationwide, couples collectively spent over $80 million on premarital testing to detect just 456 syphilis cases. Engaged couples applying for marriage licenses were simply not where the infections were concentrated.
Penicillin changed the calculus. First used on patients in 1941 and widely available by 1944, it cut syphilis treatment from roughly a year to about eight days. Older arsenic and bismuth regimens cured only about one in four patients who began them; penicillin treatment was completed about four times more often because it was faster, cheaper, and far less punishing. Once the disease was easily curable, catching it through engaged couples made less and less sense.
The requirements also pushed couples across state lines. Studies found that when a state imposed testing, about one-third of the resulting drop in local marriage licenses came from couples marrying in a neighboring state without the rule, and roughly two-thirds of the drop came from couples who did not marry at all. The laws were discouraging marriage without catching much disease.
The Short-Lived HIV Testing Experiment
When AIDS emerged in the 1980s, more than thirty states considered applying the old syphilis template to HIV.5Tulane Law Review. Mandatory Premarital HIV Testing: Political Exploitation of the AIDS Epidemic Only Illinois and Louisiana enacted it. Illinois began requiring proof of an HIV test on January 1, 1988. The program cost an estimated $5.6 million per year and identified only 23 HIV-positive individuals, while marriage license applications in Illinois fell by about 14% as couples went elsewhere to marry. Illinois repealed the law in September 1989. Louisiana repealed its version in 1988.6Washington University Open Scholarship. For Better or for Worse? Mandatory AIDS Testing for Marriage License Applicants The experiment confirmed what the syphilis data had shown for decades: the marriage license counter is not where you find the people you most need to screen.
When States Dropped the Requirement
Maine became the first state to repeal its premarital examination law in 1972. Most other states followed over the next three decades. Some had expanded testing in the meantime to include rubella screening for women, since rubella in pregnancy causes severe birth defects, but those requirements fell away as childhood vaccination drove rubella down. Montana was the last state to end the practice, repealing its rubella screening requirement for women in 2019.7Montana State Legislature. House Bill 136 – Abolishing the Premarital Blood Test
What Remains Today
No state currently requires a blood test as a condition of getting a marriage license, with one narrow exception.
New York’s Sickle Cell Test
New York still requires a sickle cell anemia test for certain marriage license applicants. The statute, in the language of its era, applies to anyone “not of the Caucasian, Indian or Oriental race,” which in practice directs the test at Black and Latino applicants. A positive result does not prevent a marriage, and applicants may refuse the test on religious grounds.8New York State Senate. New York Domestic Relations Law 13-AA – Test to Determine the Presence of Sickle Cell Anemia
Information Instead of Blood Draws
At least thirteen states now require that marriage license applicants receive educational materials about HIV and other sexually transmitted infections rather than take a test.9Connecticut General Assembly. HIV Blood Testing for Marriage Licenses Approaches vary. Some states have the county clerk hand out a brochure. Others ask applicants to sign a statement confirming they received information about testing options. Michigan requires actual counseling from a health professional, with a religious opt-out. None of these informational requirements block a marriage.
Marriage-Based Immigration Still Requires a Blood Test
If you are marrying a foreign national and sponsoring an immigrant visa or green card, the medical examination required by federal immigration law still includes a syphilis blood test, a tuberculosis screening, and proof of required vaccinations covering measles, mumps, rubella, hepatitis A and B, varicella, tetanus, and others.10Travel.State.Gov. Medical Examinations FAQs Applicants with a history of syphilis or tuberculosis must document completed treatment, and the exam must be performed by a USCIS-designated physician. The requirement applies regardless of what state the couple lives in, so the syphilis blood test that states spent decades retiring from marriage licenses still appears in federal immigration files.