Brand new at this and don't have good grip yet on cMs ranges for relationships, especially when number falls in between stated ranges for relationships.

Both my dad and I have taken DNA tests from 23 and Me. We share a match, and 23 and Me says this person and I likely share a set of grandparents...that we are first cousins (we share 8.92% DNA, and 664 cMs across 21 segments). My dad shares 1,260 cMs with this match across 35 segments (can't see percentage shared).

My father is the only child his parents share, so match and I can't be (whole) first cousins.

Match is likely my first cousin once removed (father's first cousin) or is it possible that match is my half-aunt/uncle (father's half sibling, unknown to us from other relationship had by my paternal grandfather)?

1 Answer 1


Try DNAPainter for a set of possible (probable) relationships.

664cm has options for you; while 1260cm has options for your father.

Hopefully you can find a pair of relationships that satisfy both of you.

For example, it shows a 69+% probability of a 1C match for your dad, and a 44+% probability for a 1C1R for you. Not saying that's the truth, but that's a possibility.

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