Over the past three decades, external forces impinging on the family have transformed parents' and, therefore, children's lives.
( ( ( ( ( ( Over ( the ( past ( three decades ) ) ) ) ( , ( ( ( external forces ) ( impinging ( on ( the family ) ) ) ) ( have ( transformed ( parents ' ) ) ) ) ) ) and ) , ) ( therefore ( , ( children ( 's lives ) ) ) ) ) . )
(ROOT (S (S (PP (IN Over) (NP (DT the) (JJ past) (CD three) (NNS decades))) (, ,) (NP (NP (JJ external) (NNS forces)) (VP (VBG impinging) (PP (IN on) (NP (DT the) (NN family))))) (VP (VBP have) (VP (VBN transformed) (S (NP (NNS parents) (POS ')))))) (CC and) (, ,) (S (ADVP (RB therefore)) (, ,) (NP (NNS children)) (VP (VBZ 's) (NP (NNS lives)))) (. .)))
In the last 30 years the parents have been transformed and in turn so have the children.
( ( In ( the ( last ( 30 years ) ) ) ) ( ( the parents ) ( ( ( ( have ( been transformed ) ) and ) ( in ( ( turn so ) ( have ( the children ) ) ) ) ) . ) ) )
(ROOT (S (PP (IN In) (NP (DT the) (JJ last) (CD 30) (NNS years))) (NP (DT the) (NNS parents)) (VP (VP (VBP have) (VP (VBN been) (VP (VBN transformed)))) (CC and) (VP (ADVP (RB in)) (VBP turn) (RB so) (VP (VB have) (NP (DT the) (NNS children))))) (. .)))