A mum has been left heartbroken after discovering her entire life has been 'one giant lie' covered up for more than 35 years.
Her 24-year-old daughter explained how she took an at-home DNA test for fun - but was shocked to discover her half-auntie was actually her full auntie.
Confused, her auntie showed the results to the mum, who burst into tears at the sight of the piece of paper.
Taking to Reddit, she said: "I took one of those ancestry DNA tests and when it came back it showed that I was way too close in DNA to my half auntie, basically showing that she was my full auntie.
"It also showed family members that shouldn't have come up from my auntie's father's side. My auntie told my mum, 55, and basically realised my mum's father (my grandpa) isn't actually her dad.
"My mum had gone 35+ years thinking her (technically) stepdad was her actual dad when her real dad died when she was 18."
She went on to explain how her grandma must have conceived her with her first husband - but passed it off as with her second.
"She was obviously super upset about it as I practically accidentally turned her whole life upside down," she added.
"I feel so awful even though she tells me it's obviously not my fault.
"She says it doesn't change anything, that my grandpa is still my grandpa, which I wasn't going to think differently anyway."
The mum is going to visit her 94-year-old 'dad' to tell him everything because she is worried it could impact his will and other legal documents.
"She is so sad because she knows it's going to break his heart because he doesn't know she's not his daughter either," she added.
"I opened the worst Pandora's box mess of a situation. Her bio dad is the prior husband and the later husband is the 94-year-old.
"She believed she was the later husband's daughter when she's actually prior husband's daughter.
"Grandma had an affair and told my mum at 18 that the later husband was her dad. Grandma passed years ago so we can't ask."
But commenters on Reddit aren't sure whether it is worth revealing the truth.
Responding to her post, one user said: "I understand the honesty but I am not sure if you should tell him. Does it really change anything for your mother?
"He is 94, he shouldn't deal with this stuff but instead have a few more happy years."
Another user added: "My grandpa told my mother he was not her real father a few years before he died.
"He had known all along, my mum had no idea whatsoever.
"It turned her right upside down for a while, but she made it through, I think your mum will too. It gets better with time."
A third user said: "My dad has found four half-siblings in the surrounding small towns via DNA tests and I'm sure there are more.
"You didn't mess anything up, DNA tests are just a tool for clarity that wasn't available.
"And the man that raised your mum is her dad. He just is. He doesn't need to know otherwise."
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