Grandma is showing dna matches with four “1st cousins” who are all supposedly first cousins themselves. The matches are 1211, 1175, 1138, and 904 cms. There is also a match of 972 who is a brother to the 1211 match. We have reason to suspect that one of these matches is somehow a half sibling. Not sure how to proceed. Three of them being that high seem suspect.

Thoughts or suggestions?


2 Answers 2


From the The Shared cM Project 3.0 tool v4 none of those match results suggest half siblings as being more likely than, or anywhere near as likely as, first cousin relationships:

For only the highest three does half sibling come into any kind of contention but in each case comes with a qualifier like:

this relationship has a positive probability for 1211cM in thednageek's table of probabilities, but falls outside the bounds of the recorded cM range (99th percentile)


This is why it's so confusing. Grandma never knew who her dad was or even for certain what his name was. She has done DNA testing on 23 and Me and also on Ancestry.com. Both sites point to the same family as her closest matches. that family had six girls and two boys. One of the sons lived in Portland for a few years where she was born. Around the same time several of his sisters relocated from Wisconsin where the family originally was from to California. She has no closer matches than those I listed other than three of her grandkids who have tested. She was born in 1932 ... certain things just weren't talked about back then. She is desperately seeking closure and peace of heart in her old age. We are just completely stumped.

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