TWINSBURG, Ohio—The FBI is interested in us.

No, we’re not “persons of interest.” We are interesting persons. My brother and I are identical twins. And the FBI has been supporting West Virginia University’s twin studies here for years.

But why here? The answer is in the name: Twinsburg.

For the last 21 years, this small town in Ohio has lived up to its name during the annual Twin Days Festival. This year, we are here with 1,917 other sets of multiples.

But back to the FBI and science. Apparently, one of the greatest tests of a facial recognition program is telling identical twins apart.

“I think we need differentiate between similar individuals more because it will make the systems more robust,” said Jeremy M. Dawson, an associate professor at West Virginia University.

So twins are helping to improve a face recognition program you might find running in a government building. But better biometrics aren’t just of interest to U.S government.

Look at last week’s big unveil of the new iPhone X from Apple. Its “Face ID” program makes a 3-D scan of your face that you can use to unlock your phone or pay for things. (Maybe we should buy one just to figure out if identical twins can trick it.) This technology is only going to get more pervasive in the coming years.

Face scanning isn’t the only way we’ve guinea-pigged ourselves for science at the Twin Days Festival:

  • We were recorded reading the same strange passage about rainbows and pots of gold (so that a computer program could try to tell us apart by voiceprint).
  • We submitted spit to have our DNA sequenced (to confirm our identicality).
  • We sipped and swished shots of milk (to gauge ability to taste fat) and clear liquid tinctures (to measure our sensitivity to sweet and bitter).
  • We took surveys on social media use and online news habits (to see if we’re both news junkies).

We weren’t alone. We sat shoulder-to-shoulder with hundreds of other twins — identical and fraternal — being sampled, questioned, and scanned in the name of science.

As identical twins, we share 100 percent of our genes. That’s how we start out at birth. But then the world works on us.

Watch and test how two identical twins grow, and age, and ultimately die, and you have in front of you the best natural experiment for separating the contributions of our genes and our environment. If researchers can understand “nature vs. nurture” in twins, it will be easier to figure out for all the non-twins out there. And that, said Chance York, an assistant professor at Kent State University, is why researchers make the yearly pilgrimage to Twinsburg.

When we asked him about what science would do if there were no twins to experiment on, he said: “the non-scientific, non-tactful answer is that we’d be screwed.”