(S (S (SBAR (IN While) (S (BASENP (DT some) (JJ religious) (NNS groups)) (VP (VBP have) (VP (VBN hailed) (NP (BASENP (NNS studies)) (SBAR (WHNP (WDT which)) (S (VP (VBD found) (BASENP (JJ positive) (NNS results)))))))))) (COMMA ,) (S (BASENP (NNS skeptics)) (VP (VP (VBP have) (VP (VBN challenged) (NP (BASENP (DT the) (JJ very) (NN notion)) (PP (IN of) (S (VP (ADVP (RB scientifically)) (VP (VBG examining) (BASENP (NN prayer))))))))) (CONJP (COMMA ,) (CC and)) (VP (VBP have) (VP (VP (VBN described) (BASENP (JJ past) (NNS studies))) (PP (IN as) (ADJP (ADJP (JJR flawed)) (CC or) (ADJP (ADVP (RB even)) (ADJP (JJ fraudulent)))))))))) (PERIOD .))