If you're keen to learn a little more about your family history, be warned - it might come with some unwanted revelations.
Nobody knows this more than TikTok user Matilda, who posted a video revealing how she was initially excited when her boyfriend bought her a DNA-testing kit for her birthday in September.
"My mum is adopted and I never really knew my biological father," she explained in the video.
"So I was mostly interested in the health info to see if there was anything to watch out for."
She added that her then-boyfriend also bought one for himself, "as they were on sale".
"So we got the results back a month later and I was looking through the list of genetic relatives because the only person that I know that I'm technically related to is my mum," Matilda recounts in the clip.
"And I scrolled down and turned to my boyfriend at the time and said, 'hey this is pretty nifty, I'm related to someone with the same name as you.'
"AND THAT'S HOW I I FOUND OUT I WAS DATING MY COUSIN."
The video has racked up over 500,000 views, with followers clamouring for a follow up to explain more about that fateful moment.
In 'part two', Matilda revealed she initially thought the pair were most likely third cousins, as they shared great-great-grandparents.
"However I was able to do a bit of research into my father's side of the family sn I found someone that had done a genealogical report back to the 1500s," she added.
"Based on the info from that research, as well as the percentage of DNA my ex and I shared which was a bit too high to be cousins, I'm fairly confident we are actually second cousins, related through my paternal great grandmother."
It goes without saying Matilda and her now-ex decided to part ways pretty soon after that.
Commenters expressed sympathy, but also couldn't help but see the funny side of the situation.
"What in the New Girl," one person joked, referring to a storyline on the popular comedy.
"As soon as you said he got one for himself I knew it would be something like this," wrote another.
"I would die on the spot," added another.