A DNA test almost ruined Christmas for one family after it revealed one daughter has a different dad.

Reddit user Snorkels721 bought the DNA testing kits for his mum, dad, brother and two sisters for Christmas.

But he said his mum “started freaking out” and urged the family, believed to be from the US, not to use them.

The siblings then realised at least one of them might not have the same dad after hearing their parents “fighting upstairs for an hour”.

Later that day the mum was forced to admit she had her eldest daughter with another man – who sadly died shortly after she was born.

Her other children’s dad helped her look after her daughter and said she kept them in the dark about the truth because it was “too painful” to discuss.

The post has since been liked 143,000 times and has prompted people to share their own stories about DNA tests.

The original post, written by Snorkels721, said: “Earlier this year, AncestryDNA had a sale on their kit.

“I thought it would be a great gift idea so I bought 6 of them for Christmas presents.

“Today my family got together to exchange presents for our Christmas Eve tradition, and I gave my mom, dad, brother, and 2 sisters each a kit.

“As soon as everyone opened their gift at the same time, my mom started freaking out.

“She told us how she didn’t want us taking them because they had unsafe chemicals.

“We explained to her how there were actually no chemicals, but we could tell she was still flustered.

“Later she started trying to convince us that only one of us kids need to take it since we will all have the same results and to resell extra kits to save money.

“Fast forward: Our parents have been fighting upstairs for the past hour, and we are downstairs trying to figure out who has a different dad.

“Our parents are fighting and my dad might not be my dad.”

However, he later added that “Christmas isn’t ruined” and said it turned into a “Christmas miracle”.

He said: “CHRISTMAS ISN’T RUINED! My FU actually turned into a Christmas miracle. Turns out my sisters father passed away shortly after she was born.

“A good friend of my mom's was able to help her through the darkest time in her life, and they went on to fall in love and create the rest of our family.

“They never told us because of how hard it was for my mom.

“Last night she was strong enough to share stories and photos with us for the first time, and it truly brought us even closer together as a family.

“This is a Christmas we will never forget. And yes, we are all excited to get our test results. Merry Christmas everyone!”