Grab your magnifying glass and amateur videos, sex in weird placesget ready to investigate as Mashable uncovers Big/Little Mysteries.

When 60-year-old genealogist Megan Smolenyak took one of the first direct-to-consumer DNA tests from 23andMe in late 2007 she unearthed her own family mystery.

"My very first experience was a big surprise," she said during a recent phone call. "I discovered my dad's brother was his half-brother."

The popular spit tests from 23andMe, Ancestry.com, and MyHeritage are just one tool Smolenyak uses to trace families' roots as a genealogy detective who has chronicled Michelle Obama's slave origins and unearthed the true identity of Annie Moore, the first documented Irish immigrant in the U.S. The tests are crucial for exposing secrets from everyday people to big-name celebrities and politicians. Her own experience was an "autosomal" surprise, meaning something uncovered from a chromosome analysis thanks to the advent of readily accessible DNA testing.

It's nearly impossible to know how often testers find surprises in their results, as reporter Libby Copeland wrote in her 2020 book, The Lost Family: How DNA Testing is Upending Who We Are. But many cases involve unknown siblings from secret relationships, unexpected ethnic backgrounds, and an unfortunate pattern of hidden incest.

Smolenyak, who is from the Washington, D.C. area but now lives in Florida, first caught the genealogy bug in sixth grade when her teacher sent students on a quest to find where their surnames originated.

She says her dad unwittingly misinformed her that it stemmed from the former Soviet Union. Years later in the early 2000s, she tracked down an obscure ethnic group in present-day Slovakia that was the true origin of her family name.

For the past several decades she's tackled genealogical mysteries big and small, making headlines when she cracks an intriguing case as an ancestry investigator for hire.

Adept at digging through online and IRL records, she's been told she's the "secret sauce" for so-called seekers trying to find family members or accurate family histories. She's taught herself the tricks of the trade over the years, but warns that it's a hard career path. "To be a genealogist is to be dismissed," she said. Most so-called genies — that's what genealogists call themselves — get into it as a hobby trying to crack their own family mysteries, so people lump in career-genies with hobbyists.

During our conversation she emphasized her work with the U.S. Army. She finds living relatives for unaccounted soldiers from World War I, II, the Korean and Vietnam wars and has encountered a lot of surprises of the genetic variety. While working more than 1,580 cases for the military, she's gone deep into family dynamics and seen "people of all stripes."

"It's not uncommon for me to know more about soldier's family than they [do] themselves," she said.

She said she's cold-called at least 10 different families to let them know they had a brother they didn't know about that died in a war. She calls this event "the surprise half sibling."

"You just can't get bored" discovering all these stories, she said. But it also "keeps you humble as a genealogist."

In one case she told a man about a half brother he didn't know about who was only six months younger. He had been killed in Korea, but the man's whole family flew from California to Arlington National Cemetery for a memorial service for a relative they never knew existed.

Smolenyak has had plenty of cases of what she calls "pure denial." When she tells families about a secret sibling, "they don't want to hear that someone stepped out," she said. She said we tend to think of our ancestors as straight-laced and in line with societal expectations.

She's discovered instances where the oldest daughter had a child out of wedlock and that baby was raised as a younger sibling. She mentioned actor Jack Nicholson as a well-known example of someone who lived with an older sister who turned out to be his mother.

"It was easier to hide your secrets," she said about generations before DNA testing and online records. "Now you can’t take your secrets to the grave."

As the former chief family historian and spokesperson at Ancestry.com until 2011, she saw first hand how at-home testing has unlocked more and more family mysteries.

Since 2016, the AncestryDNA app that accompanies the company's home testing kit has grown from more than 51,500 downloads each year to more than 2.2 million in 2021 so far, according to data from Apptopia. The app gives a breakdown of your ethnic background and connects you to potential relatives.

The 23andMe app that has similar features has seen comparable growth with under 95,000 total downloads in 2016 jumping to over 2.1 million this year, according to Apptopia.

While DNA testing has surfaced many discoveries, it also opens up other issues. You're giving out private biological information to large corporations that may be emboldened to do what they want with your information. The tests also offer more limited ancestry detail for users who aren't white. Your spit also unlocks information about your relatives even if individual family members have no interest in taking a DNA test, or letting a corporation sell their DNA data to pharmaceutical companies.

Still, Smolenyak sees the benefits in pairing DNA tests with archival research. "For hard core genies we love picking through the archives," she told me.

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She resurfaced former secretary of state Hillary Clinton's roots in 2015 mostly for fun while Clinton was on the presidential campaign trail. While she knew she wasn't the first to look into Clinton's family tree, she discovered one of her grandmothers' information had been recorded incorrectly elsewhere. It wasn't anything earth-shattering, just a mix up about the parents of another woman with the same name as Clinton's grandmother, but it showed how inaccurate information sticks around and misinforms future research. "Bad info starts to outshout the good," Smolenyak bemoaned. She was surprised to find the mistake for somebody whose every move was so scrutinized.

Smolenyak has used her own sleuthing skills to make sure she wasn't related to her husband, who has the same last name.

"I suppose the fact that I happen to be a Smolenyak who recently married a Smolenyak from one of the other lines gives me reason to sigh with relief," she wrote in an article about her findings.

In a recent email she summed up any confusion: "I'm a Smolenyak by birth and by marriage (beat them odds). It's why I sometimes sign my books Smolenyak-squared."

Smolenyak relishes a good challenge that requires a trip to the archives or months of searching an online database with spelling variations of a last name. "If you're trying to solve a history mystery, each generation adds a potential surprise," she noted for anyone hesitant to learn about their family's past.

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As to DNA testing she advises: "If you don't want to know, don't test."

She doesn't want everyone to assume their father isn't who they thought, but there's a strong chance "you're going to find something unexpected." It's how these genetic mysteries tend to unravel.

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