(S (S (BASENP (DT The) (NN sheep) (NNS researchers)) (VP (VBP postulate) (SBAR (IN that) (S (NP (BASENP (JJ low) (NNS levels)) (PP (IN of) (NP (BASENP (NN aromatase) (NNS hormones)) (PP (IN in) (NP (BASENP (DT the) (NN brain)) (PP (IN of) (BASENP (DT a) (JJ developing) (JJ male) (NN sheep) (NN fetus)))))))) (VP (MD may) (VP (VB have) (VP (VP (VP (VBN kept) (BASENP (DT the) (NN brain))) (PP (IN from) (S (VP (ADVP (RB fully)) (VBG masculinizing))))) (COMMA ,) (S (VP (VBG leading) (PP (TO to) (BASENP (ADJP (RB sexually) (JJ male-oriented)) (NNS rams)))))))))))) (PERIOD .))