A DNA Case Study of Unknown Parentage

Family secrets have a way of persisting across generations, leaving descendants with questions that documents alone cannot answer. In this case study, we explore how traditional genealogical research, paired with modern DNA analysis, revealed the truth about a man born in California during World War II. For years, the identity of his father remained unknown—until now.

The Family Mystery

Calvin* was born in 1941 in Los Angeles County, California, to a young unmarried woman named Margaret. His birth certificate listed no father. Margaret never married and never disclosed Calvin’s paternity to him or others in the family. The question lingered for decades, passed down from Calvin to his children and grandchildren.

Family stories hinted that a man named William Ramsay may have been Calvin’s father. The rumor was vague—based on conversations from long ago, and without documentation to support it. William was known to have lived in California around the time of Calvin’s conception, and he reportedly “knew” Margaret in some capacity. But without records, there was no proof—just speculation. Calvin passed away in the early 2000s. Years later, his daughter—referred to here as the test subject—decided to find out the truth. She turned to DNA.

Traditional Research: Building the Timeline

The first step in resolving the mystery was reconstructing the lives of Margaret and William Ramsay to determine whether a relationship between the two was even plausible.

Margaret was born in 1919, and public records show she was living in Los Angeles by the 1930s. She worked as a secretary and resided with her widowed mother. Margaret’s life during the early 1940s was relatively stable, and her address placed her in central Los Angeles, near many wartime industries.

William Ramsay, born in 1911 in Utah, was the son of George Ramsay and Eliza. By the late 1930s, he had moved to California and was living in Los Angeles. Multiple records—including city directories—confirmed that William was working and residing within a few miles of Margaret’s neighborhood during the years 1940–1942. He was single and in his early 30s—Margaret was 22 when Calvin was conceived. While there was no direct evidence (such as letters, photos, or employment records) proving a relationship between William and Margaret, their geographic and social proximity during the critical period made the hypothesis reasonable.

DNA Evidence: A Genetic Web Unfolds

When Calvin’s daughter—referred to here as the test subject—decided to pursue DNA testing, her goal was simple: to determine whether the rumors about William Ramsay were true. She took an autosomal DNA test through AncestryDNA, the largest consumer DNA database, to maximize the likelihood of finding relevant matches. She also uploaded her raw DNA data to GEDmatch, a third-party site that allows for more detailed comparison tools and access to matches from other testing platforms. Within weeks, the test subject received her results. Among the thousands of matches, three stood out as particularly significant: they shared between 220 and 560 centimorgans (cM), placing them in a range consistent with half first cousins, first cousins once removed, or second cousins. These are strong matches—indicative of a shared great-grandparent or grandparent-level relationship.

To make sense of these numbers, it’s helpful to understand what a centimorgan represents. A centimorgan is a unit of genetic linkage; the more cM two people share, the closer their likely relationship. For instance, first cousins typically share around 850 cM, while second cousins share approximately 200–400 cM. Half first cousins or first cousins once removed fall in a middle range. This means that matches sharing more than 200 cM are likely to be quite close relatives—well within the range needed to identify shared ancestors.

The test subject’s closest match, Match 1, shared 558 cM across 27 segments, which immediately suggested a very close familial link. After constructing this individual’s family tree using public records and shared family trees on Ancestry, it was determined that they were a descendant of Mary Ramsay, the sister of William Ramsay. That placed the match as a first cousin once removed or potentially a half first cousin to the test subject—both relationships that are entirely consistent with William being her grandfather. Match 2, sharing 287 cM across 17 segments, was shown to descend from Charles Ramsay, another sibling in the Ramsay family. While a more distant match than Match 1, this relationship still pointed strongly to shared ancestry from George and Eliza Ramsay, the parents of William, Charles, and Mary. Match 3 shared 222 cM across 14 segments, and while their tree was less complete, they had several known relatives in common with Match 2. After additional research, Match 3 was also confirmed to be a descendant of the Ramsay family—again pointing to shared roots in George and Eliza.

To ensure that these shared connections weren’t the result of “pedigree collapse” (when cousins intermarry, causing the same ancestors to appear multiple times in a person’s family tree), we examined the test subject’s maternal line. There was no overlap in geographic location, ethnicity, or surnames with the Ramsay family. This ruled out the possibility that the matches were on her mother’s side. Additionally, no close matches emerged from any unrelated family lines on the test subject’s tree that could explain the Ramsay DNA. This absence of alternative explanations helped strengthen the case for a direct paternal connection to the Ramsays.

One important clue was that all three of these key matches were descended from different Ramsay siblings. In essence, each match represented a different branch of the same family tree, and yet they all pointed toward one shared couple at the top: George and Eliza Ramsay. This suggested that the test subject was likely descended from another of their children—specifically one whose line wasn’t already represented in the matches.

Given that William Ramsay had lived in Los Angeles at the right time and was unmarried, he became the most plausible candidate. There were no known descendants from any of the other Ramsay siblings who had lived in California in the early 1940s. In addition, no DNA matches were found who descended from Fred or John Ramsay, the remaining brothers. This network of matches formed a triangulated cluster—a group of people who all share DNA with each other and a common ancestor. This type of clustering is a powerful tool in genetic genealogy. It allows researchers to verify that matches are related through the same ancestral line rather than through coincidental or multiple unrelated connections.

Altogether, the DNA evidence painted a coherent and compelling picture. The concentration of mid-to-high centimorgan matches descending from George and Eliza Ramsay—alongside the total absence of similarly strong matches from any unrelated line—strongly indicated that Calvin was the son of one of their children. And given all known circumstances, that child was almost certainly William Ramsay.

Triangulating the Relationship: All Roads Lead to William

To strengthen the hypothesis, we mapped out possible relationships using the Shared cM Project and relationship probability tools. The results indicated that if William Ramsay were Calvin’s biological father, the test subject would be a grandchild of George and Eliza Ramsay. The shared DNA amounts between the test subject and Ramsay descendants were consistent with first cousins once removed—a perfect fit if William was Calvin’s father and his siblings were the parents or grandparents of the matches.

Further points supported this conclusion:

• No other children of George and Eliza had known descendants who lived in California in the early 1940s.
  
  
• The test subject had no DNA matches aligning with the paternal lines of George and Eliza’s other sons (e.g., Charles or Fred).
  
  
• A match from William’s maternal line—Eliza’s family—helped confirm the descent was not just through George’s side.
  
  

The convergence of these clues, both documentary and genetic, ruled out alternative explanations and aligned perfectly with the theory that William Ramsay fathered Calvin in 1940.

Conclusion: A Silent Certificate, a Loud Genetic Answer

Although Calvin’s official records never named his father, the combination of modern autosomal DNA testing and traditional genealogy left little doubt. The web of centimorgan relationships, the geographic overlap, and the absence of counter-evidence all point to a single, persuasive conclusion:

William Ramsay was Calvin’s biological father.

This case shows the transformative power of DNA when paired with a careful, methodical research process. Where paper records are silent—or sealed—DNA can uncover the truth buried in our chromosomes.

Are You Searching for a Missing Parent or Grandparent?

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Get started today. Your family story deserves to be told.

James

*Names changed for privacy

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