As an organizing structure, family has always had its costs and benefits. It provides love and support. But it also encourages nepotism and tribalism. We tend to put our family’s well-being above that of society’s. Perhaps the reality of One Big Family will tip the balance toward the good.

I understand the privacy concern. But like it or not, the transparency train isn’t slowing down. Births and deaths are public records.

And for the vast majority of us cousins, I don’t foresee much harmful fallout from semi-public family trees, especially since the first names of living relatives usually remain hidden. These trees are exposing the names of uncles and aunts, not credit cards numbers and passwords. Mr. Schoenberg argues that many of us suffer from “narcissistic paranoia.” The world overflows with so much data, no one really cares who your sister is.

Another big problem: accuracy. Like Wikipedia, the shared websites allow collaborators to edit your family tree. Geni has more than eight million users, and about 120 volunteer curators. Mistakes can creep in. Documentation is sometimes still sparse. The tree’s accuracy will, I think, improve as more evidence is added. But it will never be perfect. Some avant-garde genealogists call their practice “quantum genealogy.” Traditional genealogists demand rigorous proof of every relationship, but the new, less cautious genealogists argue that we have to work with probabilities. We may never know for sure that X is Y’s uncle, but we can make educated guesses. (I think both types of genealogy have their place.)

The farther you go back, the more quantum it gets. According to Geni, my 97th great-grandfather is King David from the Bible. So what are the chances that I’m actually a direct descendant of the Goliath slayer? Count me a highly doubting Thomas. But it’s still fun to dive into the research and try to verify it.

In addition to using crowd-sourced trees, I’m trying to build my family list with genetic testing. I recently sent my saliva off to 23andMe (the F.D.A. has suspended the health-related part of 23andMe, but the ancestry service remains open). The result? I found more than a thousand fellow spitters who share enough genetic material that 23andMe says we are probable cousins. One such distant cousin: my wife. This was a tad jarring. Not to mention that it set off an avalanche of bad inbreeding and hillbilly jokes from friends. But the truth is, my wife and I aren’t unusual.

And that means, my cousin, you’re invited to a little get-together I’m planning: the mother of all family reunions. Next year, thousands of my relatives — from first cousins to 26th cousins — will, I hope, gather to eat some barbecued chicken, play tug of war and debate the meaning of family in this era of the global village. It’s my admittedly quixotic dream that when we realize that we’re all related, we’ll treat one another with more civility.