Then, too, there have been the campaigners who have gone to what some regard as opposite  if the head of a committee is known to be a man or a woman, then chairman or chairwoman must surely be the proper denotation; if the sex of the person is not known, then chairperson , though awkward-sounding, is the preferred form.
( Then ( , ( ( ( ( too ( ( , ( ( there ( have ( been ( ( the campaigners ) ( who ( have ( gone ( to ( what ( some ( ( regard ( as opposite ) ) ( if ( ( ( the head ) ( of ( a committee ) ) ) ( is ( known ( to ( be ( ( ( a man ) or ) ( a woman ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) , ) ) ( ( then ( ( chairman or ) chairwoman ) ) ( ( must surely ) ( be ( the ( proper denotation ) ) ) ) ) ) ) ; ) ( ( if ( ( ( the sex ) ( of ( the person ) ) ) ( ( is not ) known ) ) ) ( , ( ( then ( chairperson ( , ( though ( awkward-sounding , ) ) ) ) ) ( is ( the ( preferred form ) ) ) ) ) ) ) . ) ) )
(ROOT (S (ADVP (RB Then)) (, ,) (S (ADVP (RB too)) (PRN (, ,) (S (NP (EX there)) (VP (VBP have) (VP (VBN been) (NP (NP (DT the) (NNS campaigners)) (SBAR (WHNP (WP who)) (S (VP (VBP have) (VP (VBN gone) (PP (TO to) (SBAR (WHNP (WP what)) (S (NP (DT some)) (VP (VBP regard) (PP (IN as) (NP (NN opposite))) (SBAR (IN if) (S (NP (NP (DT the) (NN head)) (PP (IN of) (NP (DT a) (NN committee)))) (VP (VBZ is) (VP (VBN known) (S (VP (TO to) (VP (VB be) (NP (NP (DT a) (NN man)) (CC or) (NP (DT a) (NN woman)))))))))))))))))))))) (, ,)) (NP (RB then) (NN chairman) (CC or) (NN chairwoman)) (VP (MD must) (ADVP (RB surely)) (VP (VB be) (NP (DT the) (JJ proper) (NN denotation))))) (: ;) (S (SBAR (IN if) (S (NP (NP (DT the) (NN sex)) (PP (IN of) (NP (DT the) (NN person)))) (VP (VBZ is) (RB not) (VP (VBN known))))) (, ,) (NP (NP (RB then)) (ADJP (JJ chairperson) (, ,) (IN though) (JJ awkward-sounding) (, ,))) (VP (VBZ is) (NP (DT the) (JJ preferred) (NN form)))) (. .)))
The gender of the person in question will determine the proper denotation.
( ( ( The gender ) ( of ( ( the person ) ( in question ) ) ) ) ( ( will ( determine ( the ( proper denotation ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN gender)) (PP (IN of) (NP (NP (DT the) (NN person)) (PP (IN in) (NP (NN question)))))) (VP (MD will) (VP (VB determine) (NP (DT the) (JJ proper) (NN denotation)))) (. .)))