Boston ? I always thought that genealogy was for people whose blood ran blue. It was for folks who traced their ancestry to the Mayflower or the American Revolution, not those who came over in steerage one step ahead of the Cossacks.

So when the New England Historic Genealogical Society published the family connections between presidential candidates and celebrities, I was an amused bystander. John McCain is the sixth cousin of Laura Bush? Hillary Clinton is the ninth cousin twice removed of Angelina Jolie? Barack Obama is related to everyone from the Bushes to Brad Pitt? How American, I thought, to search an entire family tree to connect with the rich and famous who live, twice removed, on some distant branch.

On a lark, I went to visit D. Brenton Simons, the genial head of NEHGS, the society founded in 1845. Simons has so many American presidents in his own ancestry that he stops counting after Washington, Adams, Van Buren and FDR. But what he finds most fascinating are the everyday ordinary searches through the 200,000 books and the 28 million manuscripts, papers and diaries that fill the building in Boston’s Back Bay.

“You can be related to a king or a horse thief,” says Simons, who shows no favoritism for either lineage. “We all make discoveries that surprise and enlighten us.”

So it is that I casually handed over a few names and dates from my own memory bank. I didn’t find a king or horse thief or Hollywood star, but I found a family secret. A garden-variety secret, I am sure, but a secret nonetheless.

My grandparents were married on Feb. 3, 1914. Five months before my mother was born on July 7, 1914.

Funny how data can set your head spinning. What did this say about my grandparents and the origin of their long, loving, imperfect marriage? About their passion or imprudence or the world they lived in 95 years ago?

Suddenly, my grandmother, whom I remember with great fondness as a cleanliness freak, the subject of much family humor, comes alive as a young woman. Suddenly, my grandfather, who led me by the hand into Red Sox Nation, is a young man. Were they lovers whose affection culminated happily in marriage? Or was this a shotgun wedding? What was it like in 1913 for a young couple to find that she’s pregnant? What happened if and when they told their parents?

And what of my mother, who never, at least consciously, knew this? My aunt cannot remember hearing the story of her parents’ courtship. There is no wedding photo. While we celebrated their 40th anniversary, none of us can even remember what time of year that party was held.

Did this secret infiltrate all their, our, lives? A lot or a little? There is, for example, my great-grandmother, who regularly warned her beautiful granddaughter – my mother – that she would come to no good. Am I required now to rewrite that old woman’s malevolence differently, as colored by her own daughter’s experience? Am I required to rethink the legacy my grandparents left me, beyond the soup pot that I cherish? Too soon old, too late … curious.

There are other bits of paper in my genealogical binder. It’s moving to see the name of the actual ship that brought my family to America and the naturalization papers that required them to “renounce forever all allegiance and fidelity” to Czar Nicholas II – which they must have done with pleasure.

But what we really want from the generations past are not just the facts or the DNA. We want the stories. Love, passion, success, disappointment, humanity. There may be no way to know – really know – their interior life. But how many of us would trade in the data for one good diary? Will we remember that in our own “estate planning”?

Maybe you read about the Connecticut teenager, Addie Avery, who searched her lineage back to a 17th century ancestor hanged for witchcraft. She’s petitioning the state to exonerate her foremother. Recently, David A. Wilson, a black journalist, and David B. Wilson, a white restaurant owner, found their connection through a slave-owning ancestor. One generation’s shame becomes another’s rich tapestry. One generation’s secret becomes another’s source of wonder.

“We all have tens of thousands of cousins,” says Simons, whose researchers connected Clinton with Jolie, Obama with Bush. “You can walk down the street right past a third or fourth cousin and not know it.”

But how I wish I could stop one couple on the street for just a question or two. The couple who were married on Feb. 3, 1914.