The proposed relationship of Harold John Schonfeld as the father of Harold John Schonfeld and Jack Harold Schonfeld is supported by DNA evidence indicating shared ancestry within the family lines.

Specifically, DNA evidence confirms a 1st cousin, twice removed relationship between JS (a descendant of the Harold John Schonfeld ancestral line) and DS (a descendant of the Jack Harold Schonfeld ancestral line) with a shared segment of 600.65 cM across 19 HIR segments.

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