DNA tests like 23AndMe and Ancestry are laying bare the frightening extent of incest in the US - including woman who discovers her ex-lover was her BROTHER

DNA tests that arrive in the mail, including Ancestry DNA and 23&me, are exposing the uncomfortable extent of incest in the US.  

The tests, which run for about $100, can't say explicitly whether someone is the product of incest, but the results can be taken to a third party genetic testing firm which can. 

One person who found out the disturbing truth about her family history was 39-year-old Victoria Hill, who, at a high school reunion, got chatting about family trees with an ex-boyfriend with whom she was once intimate.

His family makeup was similar to hers and upon talking to her, took the same test. A text sent to her confirmed what they had feared, saying simply: 'You're my sister.' Ms Hill says she is still traumatized to this day. 

Meanwhile, Virginia native Steve Edsel, found out via AncestryDNA that his parents were first-degree relatives, either siblings or father-daughter. 

He radiated anger at the thought of the origins of his conception, likely the result of sexual assault of his mother carried out by his grandfather. 

One 1975 psychiatry text book put the rate of children born of incest at one in a million. Subsequent research in the UK found the rate is more like one in 7,000

Incestual family relationships have garnered increased public interest after a 2004 documentary as well as exclusive DailyMail.com reporting about America's most inbred family, the Whittakers

The prevalence of incest in the US is far more common than previously thought, with research including common genealogy tests putting the rate at one in 7,000. 

Dr Jim Wilson, from the University of Edinburgh who conducted that research, said: 'That’s way, way more than I think many people would ever imagine.’ 

It’s a far cry from one 1975 estimate in a psychiatric textbook, putting the rate at about one in a million.

DNA tests that arrive in the mail, including Ancestry and 23&me, can be helpful tools in determining whether someone has genetic predispositions for certain conditions.

Still, they occasionally learn the disturbing truth about their parentage.

Babies born of incest are at increased risk of suffering birth defects, developmental delays, and genetic disorders such as blindness, hearing loss, neonatal diabetes, and limb malformations.

The risks of two siblings or a parent and child having a baby are manifold. When two closely related people have sex, and the female becomes pregnant, there is an increased risk of recessive gene disorders.

19 states where you can still marry your cousin - despite health risks 

Despite known health risks of inbreeding, marriages between first cousins are still permitted in 19 states and DC [shown]. The Whittaker family, shown here, is the most famous inbred family in the US. 

This is because children receive one copy of genes from each parent, with the harmful genetic mutations known as recessive genes being overridden by dominant genes.

When related individuals get pregnant, they decrease genetic variations, and the recessive gene they have may combine to become dominant in their child, causing many types of congenital disabilities.

In cases of incestual relationships, genetic variations from two parents decrease, and recessive genes may combine to become dominant in the child, resulting in a higher risk of a range of disorders, including low IQ, cleft palate, heart conditions, cystic fibrosis, and infant death.

People born of incest may feel like they cannot reproduce for fear of giving birth to a baby with life-threatening genetic anomalies.

One such person is 64-year-old Teresa Weiler. She found out in 1985 that her father was her mother’s brother.

She said: ‘It was only when I was walking the streets afterwards, in a daze, that it hit me: I could never be a mum.

‘There was no way I could risk having a damaged baby. I would have to give up the one thing I wanted most in the world.’

Steve, meanwhile, was born with a heart murmur that required two surgeries when he was a teen, a possible product of two sets of the same genes and mutations, though he and his wife Michelle, who has helped him on his search for the truth, can’t say for sure that his incestual origins were the cause.

Steve grew up in a foster home and was always curious about his biological family. He took his Ancestry test as part of a quest to track down his birth mom, who had given him up shortly after giving birth when she was 14, according to the Atlantic.

He also enlisted the help of CeCe Moore. Who specializes in locating people using distant DNA matches, a method that found and led to the imprisonment of the Golden State Killer. 

Since working on Steve’s case, Ms Moore now knows of well over 1,000 additional cases of people born from incest.

Most of those cases were between first-degree relatives, while the rest were the product of second-degree relatives, like half-siblings, uncle-niece, and grandparent-grandchild.

Steve was able to find a support group online set up by Ms Moore for people in his situation, and members have complained of a host of issues, including autoimmune diseases, fibromyalgia, and eye problems. However, it’s difficult to pin down incest as the cause.

One support group member, Mandy, whose last name was withheld for her privacy, found out her father was her mother’s uncle. Her mother, a cruel woman, was 17 when she gave birth to Mandy, while her uncle was in his 30s.

Her mother treated her worse than her younger brothers, and Mandy now understands that to be the reason behind her mother’s cruelty. But the situation still makes her uneasy.

She said: ‘When I go to the doctor and they ask me my family history, I wonder: “How much do I need to go into it?”’

Typically if someone wants to test for a possible incestuous relationship, they have to upload their genetic material to a third-party service. It’s not something that AncestryDNA or 23&Me disclose to customers.

The third-party tests look for runs of homozygosity, or ROH for short. The genomes of children born of incest show an ‘absence of heterozygosity,’ which explains why their DNA contains big chunks that show the father’s and mother’s genetic contributions are identical because they themselves shared much of their genetic code.

People born of incest may feel like they cannot reproduce for fear of giving birth to a baby with life-threatening genetic anomalies. One such person is 64-year-old Teresa Weiler. She found out in 1985 that her father was her mother’s brother

DNA tests mailed out by major companies have uncovered other troubling family secrets that have thrown people’s lives into a tailspin.

Iin Connecticut, Ms Hill said she was left 'traumatized' after realizing she had unknowingly committed incest with her high school boyfriend.

She told CNN she only found out the man she had grown up thinking was her dad was not her biological father after taking the home DNA test. 

Ms Hill said: 'I'll just put it out there, I was intimate with my half brother.

'I was traumatized by this,' Hill added. 'Now I'm looking at pictures of people thinking, well, if he could be my sibling, anybody could be my sibling.'

In Denver, influencer and realtor Celina Quinones decided to take a DNA test in 2016. It revealed that she and her husband had a genetic match of 62 centimorgan - a unit of measuring genetic linkage - meaning they share ancestors eight generations back.

She said: 'I was in shock. I was a little depressed over it, to be honest. But this was after we already had three kids, and all of them were healthy.

'They have 10 fingers, 10 toes, but it was just a shock.' 

Incestual relationships have received increased interest and attention in recent years, in part thanks to a 2004 documentary about the deformed, inbred Whittaker family in Odd, West Virginia.

When visiting the family, DailyMail.com was welcomed by several members, including Ray, who can only communicate via barks and grunts, and who insisted on showing reporters around the property.

DailyMail spoke with members of the family who said they were thrilled with their new creature comforts. Pictured: Timmy, Betty and Lorene. Pastor William Plumley told DailyMail.com that Timmy and Lorene had been members of the Good Hope congregation for many years and enjoy getting involved in the sermons

Currently living at the dilapidated homestead are siblings Ray, Betty, Larry and Lorene, as well as her son Timmy, all of them struggling with heartbreaking mental and physical conditions.

Ray appeared to suffer the most and excitedly communicated through noises, pointing to show items at their home in a childlike manner.

The siblings are the descendants of two sets of first cousins who got married. DailyMail.com previously revealed that the bloodline continued with a set of identical twin brothers whose children got married.

John and Henry Whittaker were born in 1897. John went on to marry his own first cousin Ada Riggs – the daughter of Mary Perkins, who was the sister of John and Henry's mother Eliza.

Ada and John had nine children, including Gracie Irene Whittaker who was born in 1920. John's brother Henry married Sally Burton and they had seven children, including John Emory Whittaker, born in 1913.

Gracie and John were first cousins, but married in November 1935 and had their first child in 1937, having 15 in total.

Many members of the family have suffered from a heart attack, while two did not make it through infancy. Some of the 15 children died early of an array of illnesses, including heart attack and cancer, believed to be tied to inbreeding.