Regarding half siblings, sent my DNA to Ancestry came to a match of half sibling at 1530 cMs @ 99% half sibling however was in contact with such match and he is claiming my father or one his two brothers had fathered him.

How can I be sure my father is the guy since neither brother or their children had taken DNA?

I am hoping to understand how to distinguish whether this match's father is the same as mine, or whether his father is one of my two paternal uncles.

  • Is it possible that your mothers are also related? Double first cousins have the same expected DNA match range as half-siblings.
    – JPmiaou
    Apr 26, 2021 at 16:53

1 Answer 1


The Shared cM Project 4.0 tool v4 suggests for 1,530cM that a half-sibling (or another close) relationship is likely but not first cousin.

For you to be first cousins (i.e. your fathers are brothers, rather than the same man) your shared cM would be expected to be in the range 396-1,397.

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