( Androgens ( ( would ( ( masculinise ( the brain ) ) ( at ( ( the ( critical period ) ) ( of ( ( 6 weeks ) ( in ( fetal life ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Androgens)) (VP (MD would) (VP (VB masculinise) (NP (DT the) (NN brain)) (PP (IN at) (NP (NP (DT the) (JJ critical) (NN period)) (PP (IN of) (NP (NP (CD 6) (NNS weeks)) (PP (IN in) (NP (JJ fetal) (NN life))))))))) (. .)))
Androgens would masculinise the brain at the critical period of 6 weeks in fetal life.
(ROOT (S (NP (DT The) (JJ fetal) (NN period)) (VP (VBZ lasts) (NP (NP (QP (RB approximately) (CD 30)) (NNS weeks)) (NP (NNS weeks)))) (. .)))