The crucial part of that world is the home where parents relate to children.
( ( ( The ( crucial part ) ) ( of ( that world ) ) ) ( ( is ( ( the home ) ( where ( parents ( relate ( to children ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ crucial) (NN part)) (PP (IN of) (NP (DT that) (NN world)))) (VP (VBZ is) (NP (NP (DT the) (NN home)) (SBAR (WHADVP (WRB where)) (S (NP (NNS parents)) (VP (VBP relate) (PP (TO to) (NP (NNS children)))))))) (. .)))
Whether parents relate to children is irrelevant to that world.
( ( Whether ( parents ( relate ( to children ) ) ) ) ( ( is ( irrelevant ( to ( that world ) ) ) ) . ) )
(ROOT (S (SBAR (IN Whether) (S (NP (NNS parents)) (VP (VBP relate) (PP (TO to) (NP (NNS children)))))) (VP (VBZ is) (ADJP (JJ irrelevant) (PP (TO to) (NP (DT that) (NN world))))) (. .)))