A couple did a DNA test for fun. It destroyed their relationship.

When you choose to do a DNA test, it’s usually to help get some clarity on where you came from.

Am I related to a King? Am I a descendent of Oprah? Do I have a long lost relative with a home in the Bahamas they fancy me visiting?

They’re the kind of hopefuls you’ve got front and centre when you send your samples off in the mail.

But one man got a little bit more than he bargained for when his ancestral discoveries lost him his girlfriend. 

Speaking of dating, we’ve got you covered. Here it is translated. Post continues after video.

In a since deleted Reddit thread, the 26-year-old explained he and his girlfriend had thought a bit of ancestry mapping might be an exciting activity to do together.

“We were having a lot of fun, but then I found out something about one of my ancestors which has now caused me to lose my girlfriend,” he said in the thread.

While searching through his DNA results, the man said “there were a few names in my family tree that I did not recognise”.

He then jumped on Google and realised one of the names he didn’t recognise belonged to an infamous serial killer.

Shocked, he told his family of his grim discovery. But it turns out they knew, and had kept the dark secret from him all his life.

They’d wanted to distance themselves from the serial killer as much as possible, so they just never spoke about it.

He then informed his girlfriend.

Who… dumped him.

“(She) broke up with me because she could not deal with the fact that I’m related to a serial killer,” he wrote.

“She told me that she loves me very much but explained that the fact I had the same blood as someone so evil has made her look at me differently.”

Reddit was on his side, and he was flooded with support.

“If she let ancestry.com results come in the way of your relationship, her foot was already half out the door and she was just looking for an out,” one person wrote.

“She was either looking for an excuse or she was a complete moron. Either way (you’re) better off,” wrote another.

Have you ever had a surprising discovery while mapping your family tree? Lets us know in the comments.