Editor's Note: Nara B. Milanich is a professor at Barnard College, Columbia University, and the author of "Paternity: The Elusive Quest for the Father" (Harvard University Press). The views expressed here are hers. Read more opinion on CNN.
(CNN) - Who's your daddy? That question, particularly apt for Father's Day, has a longer history than you might think.
According to a long-standing cultural and legal tradition, paternity is an intractable problem. Whereas the mother can be known at the moment of birth, the father, it is said, is always uncertain. DNA testing is actually a recent historical invention -- it only emerged in the 1980s. But long before the all-revealing cheek swab, scientists set out in search of a proof of paternity. They ultimately found one -- but their quest failed anyway.
As a historian whose areas of focus include history of family and kinship, childhood, reproduction, law and social inequality -- all topics linked to what I have called the conundrum of fatherhood -- I decided to probe the history of paternity testing. Here's some of what I learned:
1. The first mail-order paternity test debuted in 1921. (23andMe: What took you so long?)
In the first decades of the 20th century, scientists and the public became fascinated by the prospect of a new scientific method of verifying parentage. An array of long forgotten (and often highly suspect) methods -- fingerprinting, anthropometry, the analysis of teeth and palates, ear shape, and eye color, to name a few -- promised revolutionary new ways to identify the father.
Probably the most famous paternity tester of the era was a quirky San Francisco physician named Albert Abrams. Abrams invented a machine called the oscillophore that claimed to verify parentage through electronic blood vibrations. His contraption made newspapers around the world, and people wrote him seeking his services. The oscillophore may have been dubious, but Abrams anticipated the commercial strategies associated with the modern genetic testing industry: For $10, a patient could mail a drop of blood on white blotting paper for analysis in his lab in San Francisco.
2. These scientific developments heralded not just new methods for discovering paternity but a new understanding of what paternity was in the first place.
Traditionally, paternity was a social fact, not a biological one, discerned in two possible ways. The first was through marriage: According to the law, the mother's husband was always the father of her child. So strong was this so-called presumption of marital paternity that if a husband was located within the "Four Seas" of the English Empire at the time of his wife's conception, English common law held he was the father of her child.
As for the father of an illegitimate child, his identity was deduced from his behavior. The father was the man who had cohabitated with the child's mother or kissed the baby in public, the man whom the neighbors saw paying the midwife. The scientific methods that emerged in the 1920s were revolutionary because they suggested a different way of understanding paternity: as a physical quality located on the body rather than a social quality reflected in a man's behavior.
3. The new science of parentage had lots of practical applications. Like hospital baby mix-ups.
In 1930, an unemployed Chicago foreman named William Watkins was observing his newborn son's bath when he noticed a small piece of tape on the baby's back. It said "Bamberger" -- the name of the family that had shared his wife's hospital room. The Bambergers soon found a "Watkins" sticker on their newborn. Which had been switched -- the labels or the babies?
The Chicago case was just one of several sensational maternity ward mix-ups that riveted the American public in these years. A panel of 11 medical experts was called in to examine the two babies and four parents. But neither the Watkins and Bambergers, nor the judge who heard the case, nor the press was convinced by this newfangled expertise. As Mr. Bamberger scoffed, "I'm sick of this science business." In any event, the "science business" was inconclusive: Nine experts voted for a mismatch, but two dissented. A month after the births, the families decided to switch babies, which they did in a carefully orchestrated photo shoot.
4. Men's rights groups have been harping on paternity fraud for the better part of a century.
Paternity tests have always been about women and sex as much as men and kinship.
In 1926, a group named the Rights for Men League in Vienna, Austria, issued a call for expanded paternity testing. The group claimed that the expanded use of tests based on inherited ABO blood types would reveal women's rampant sexual duplicity. The league's demands reflected anxieties about the modern, emancipated woman that emerged in the interwar period. Today, men's rights groups often make similar demands for the expansion of DNA testing.
5. Nazis were obsessed with paternity testing.
Their obsession was a natural extension of their fixation with race. After all, to determine whether someone was Jewish or Aryan, the Nazis' genealogical definition of race required knowing the identity of an individual's parents. Nazis worried that adoption, illegitimacy and adultery could create scenarios in which Jews could hide themselves in "Aryan" families.
At the same time, Jews sought protection through the Nazis' obsession. As I write in my book, they filed thousands of suits challenging their paternity to change their own racial classification or that of their children. A woman might claim, for example, that her child had been fathered not by her Jewish husband but by her Aryan lover. The lengthy investigations that ensued in such cases could stave off deportation, and possible fathers might even be summoned from the camps to be interviewed or examined. Under the Nazis, paternity testing became a matter of life and death.
6. Paternity testing has often been inseparable from race testing.
And not just in Nazi Germany. The scientific quest for the father grew directly out of eugenics and race science. Like paternity, race was understood to be an innate physical quality, an essential truth that could be hidden, ambiguous or unknown. Scientists were fixated on revealing that essence. Today that association lives on in DNA tests that promise to reveal the truth of both parentage and race. Ethnicity remains the sap of the family tree.
7. Science destabilized, but did not necessarily replace, older ways of understanding paternity.
Just because scientific methods eventually made it possible to know the genetic progenitor doesn't mean that societies always embraced biological definitions of paternity. In 1989, the US Supreme Court considered the paternity of a child whose married mother had had an affair with another man. While DNA testing showed that the boyfriend was the progenitor, the court declared that the mother's husband was the legal father. Today, as in the past, in some circumstances, marriage still makes the father.
8. Today DNA testing is a multibillion dollar industry. What Big Paternity markets is doubt.
Because the only people who need a paternity test are those uncertain about the result, Big Paternity has to convince consumers they might not know who their father is. They cite an endlessly recycled (and patently false) statistic that 30% of people don't know the identity of their father. They form partnerships with shows such as Maury Povich's, which fetishize doubt and the promise of discovery. What's more, the marketing works. A geneticist I interviewed for my book told me that about a million paternity tests are performed in the United States each year, and 36% of industry revenue comes from "peace of mind" tests sold to private consumers.
9. DNA can identify the biological father with 99.9% certainty, yet it has not solved the "problem" of uncertain paternity.
The 100-year quest for the father culminated in a scientific method that yields genetic truth with unprecedented power and perfection. That method has become a routine part of legal practice, public policy, media culture and social life across an ever-greater swath of the globe. Yet biological truth has not resolved the conundrum of the father.
That's because it was not a lack of scientific knowledge that produced the quest for the father; the quest was always social and political. And so, whether in the era of the oscillophore or of DNA, 100 years of paternity testing has brought us no closer to knowing who's your daddy.