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To think they are my sibling? (DNA results)

(149 Posts)
PeanutButterFalcon Sun 20-Sep-20 00:15:36


I have done an heritage DNA test and have been linked to someone with a 100% chance they are a close relative (niece/nephew, grandparent, grand child, half sibling).

I have looked at my family trees and there is no link that I can see to their family. If I go back further, I would imagine, our DNA wouldn't be such a strong match. Over 25% of our DNA matches and we have the longest segment length of over 150. Although I'm not sure what the segment length means.

I cannot but help think one of my parents have had an affair and they are a sibling. I have so many questions and thoughts in my head. Are these tests reliable? How would we even go about working out if we are? I cannot ask my parents if they have and I do not think they would be honest with me anyway.

What would you do in this situation?

OP’s posts: |
gingerfreckles Sun 20-Sep-20 00:22:29

How many CM (centimorgans) is the match? A half sibling is around 1700.

greenlynx Sun 20-Sep-20 00:23:08

Do you know how old is this person?

gingerfreckles Sun 20-Sep-20 00:24:29

This might help to figure out the relationship.

Luzina Sun 20-Sep-20 00:24:43

I think this shows how dna test services can be a bit risky. I hope you figure it out OP and it doesn’t cause you too much stress flowers

Einszwei Sun 20-Sep-20 00:26:18

If you go to you can plug in the cM amount and it will give you the possible relationships.

anorangeaday Sun 20-Sep-20 00:27:01

What details do you know about them?

PineconeOfDoom Sun 20-Sep-20 00:27:32

I would do nothing, I can’t see what’s to be gained by from it. But then I would never have done the test in the first place. Non-paternity runs at about 10% in this country, and always has. Previous generations deserve their business left in the past as far as I’m concerned.

PeanutButterFalcon Sun 20-Sep-20 00:28:55

@gingerfreckles over 1700. From what I've researched a full sibling is around 2300/400 and it's below that. Part of me hopes sometimes coincidently you can get this with absolute strangers and it's not from an affair.

@greenlynx from pictures they look younger than me, maybe late teens early 20s. I haven't spoken to them to get an exact age. Definitely not old enough to be a grandparent but to old to be a niece/nephew.

OP’s posts: |
Nestme Sun 20-Sep-20 00:29:18

I'd get a proper sibling DNA test

gingerfreckles Sun 20-Sep-20 00:32:47

In my experience there are no mistakes in the tests.
Could it be a young aunt/uncle?

PeanutButterFalcon Sun 20-Sep-20 00:35:30

@Luzina I never imagined this. We have some features in the family that could be from other cultures and wanted to see my heritage. I think I just want to know the truth now.

@anorangeaday apart from the names of their family and some common DNA matches not a lot. I know where they are from but do not know if that's where the family has always lived.

I said to my mum I had a match and wanted to find her on the family tree and she just said she doesn't recognise them, but who knows. I have younger siblings that would be around the same age as them too!

@PineconeOfDoom it's a bit late for me not to do it now. As a family we have always been interested in history and our heritage. I just didn't imagine this.

OP’s posts: |
Einszwei Sun 20-Sep-20 00:36:28

With that amount of cM this person is definitely a close relation and not a stranger.

user127819 Sun 20-Sep-20 00:37:33

If you know their name and approximate age, you could search the births index for their date of birth and mother's maiden name. covers births up to 1992, is up to about 2007 I think.

Einszwei Sun 20-Sep-20 00:38:12

If you look through the shared matches, you should be able to deduce if this match is on your maternal or paternal side of your tree.

PeanutButterFalcon Sun 20-Sep-20 00:38:35

@gingerfreckles that's what I got the family tree out for. I really don't think that's possible my maternal grandparents would of been 70 and my paternal grandparents had already passed away. I've gone back as far as great grandparents and cannot see anything that suggest this.

OP’s posts: |
gingerfreckles Sun 20-Sep-20 00:41:06

Ahh ok. A little Facebook & LinkedIn stalking might help also.

VanGoghsDog Sun 20-Sep-20 00:43:45

My actual half sister only shows up as "possible cousin" on our DNA tests.

mathanxiety Sun 20-Sep-20 00:44:16

This may be way off, but do either of your parents (or maybe any grandparents) have a lost identical twin?

PeanutButterFalcon Sun 20-Sep-20 00:44:55

@Einszwei I believe it's paternal as I have a relative from my maternal side who they do not. Although it doesn't tell me if it's their dad or my dad! The other matches are all unrecognised.

I looked at DNA tests but I would need my DF's DNA and he passed away. I thought about asking a sibling to do one, however, I'm not sure if I can do this without suggesting there has been an affair somewhere, which would not be received well.

@user127819 I have looked into their family quickly today although did not think about looking for the DoB. Will do that now

OP’s posts: |
SirVixofVixHall Sun 20-Sep-20 00:59:45

That many centimorgans is a half sibling I would think. My closest match on my DNA list is 380cm, and that is my half first cousin.

PeanutButterFalcon Sun 20-Sep-20 01:03:18

@VanGoghsDog really? How much of a DNA match do you have?

@mathanxiety as far as I'm aware no. My maternal side is pretty easy to follow, however paternal not so much. Will have another look to see if anyone else's birth was registered at a similar time to them that may be a link.

@gingerfreckles I have become an expert stalker today.

It appears they have an older sibling the same age as me, and they appear to be a couple months older than a younger sibling.

From stories I have been told, my DF left after me. Suppose this gives both my parents the opportunity.

OP’s posts: |
PeanutButterFalcon Sun 20-Sep-20 01:05:48

Just to add DF came back. He would often go home to work.

OP’s posts: |
12309845653ghydrvj Sun 20-Sep-20 01:13:07

Wow, sounds like you’ve potentially stumbled upon a family secret...

If you can find their birth record or other evidence of their age, that’s a good starting point. Then go through their social media and their families, and compare with what you know about your family: e.g. if their mum worked in the same sector and geographic area as your dad, etc—any possible points of interconnection between the families. When searching for information about them, it helps to use “” (exact search term only) and -to remove any false leads. If you do their Facebook/Twitter/Instagram/Pinterest etc and the do their parents and siblings, you should have a fairly good idea about their family situation? You might be able to find companies house info that pins down addresses, birth dates and times for the family too? Maybe even properly records to suggest a time when someone moved? You can also search their name and geographic location in electoral register, I think it might give you a timeframe of how long they have lived there?

Inkpaperstars Sun 20-Sep-20 01:13:43

Can this person see you too on Ancestry? If I saw someone with that much of a DNA match to me I think I would message them. How do feel about OP? Excited or more disturbed? If your parents split after you were born it seems very possible your DF went on to father another child.

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