The proposed relationship of Sally as the mother of John Geary and Thomas Geary is supported by DNA evidence indicating shared ancestry within the family lines.

Specifically, DNA evidence confirms a distant cousin relationship between MFF (a descendant of the John Geary ancestral line) and JO (a descendant of the Thomas Geary ancestral line) with a shared segment of 13.07 cM across 1 HIR segments.

This match is consistent with their placement within these shared ancestral branches.