(S (S (NP (BASENP (DT The) (NNS researchers)) (SBAR (WHNP (WP who)) (S (VP (VBD conducted) (BASENP (DT the) (NN study)))))) (VP (VBP urge) (NP (NP (ADJP (RBR more) (ADJP (JJ open) (CC and) (JJ educational))) (NN discussion)) (PP (IN of) (BASENP (DT this) (ADJP (RB highly) (JJ stigmatized)) (NN topic)))))) (PERIOD .))