But it is patently ridiculous to refer to someone whose sex is known as a chairperson .  Chair should be reserved for the office of the chairperson, not the person holding the office.
( But ( ( ( ( ( it ( is ( patently ( ( ridiculous ( to ( refer ( to someone ) ) ) ) ( ( ( whose sex ) ( is ( known ( as ( a chairperson ) ) ) ) ) . ) ) ) ) ) ( ( Chair ( should ( be ( reserved ( for ( ( the office ) ( of ( the chairperson ) ) ) ) ) ) ) ) , ) ) not ) ( ( the person ) ( holding ( the office ) ) ) ) . ) )
(ROOT (S (CC But) (S (NP (PRP it)) (VP (VBZ is) (ADJP (RB patently) (JJ ridiculous) (S (VP (TO to) (VP (VB refer) (PP (TO to) (NP (NN someone)))))) (SBAR (WHNP (WP$ whose) (NN sex)) (S (VP (VBZ is) (VP (VBN known) (PP (IN as) (NP (DT a) (NN chairperson)))))) (. .))))) (PRN (S (NP (NNP Chair)) (VP (MD should) (VP (VB be) (VP (VBN reserved) (PP (IN for) (NP (NP (DT the) (NN office)) (PP (IN of) (NP (DT the) (NN chairperson))))))))) (, ,)) (RB not) (S (NP (DT the) (NN person)) (VP (VBG holding) (NP (DT the) (NN office)))) (. .)))
Calling someone whose sex is known a chairperson is not so intelligent.
( ( Calling ( someone ( ( whose sex ) ( is ( known ( a chairperson ) ) ) ) ) ) ( ( ( is not ) ( so intelligent ) ) . ) )
(ROOT (S (S (VP (VBG Calling) (NP (NP (NN someone)) (SBAR (WHNP (WP$ whose) (NN sex)) (S (VP (VBZ is) (VP (VBN known) (NP (DT a) (NN chairperson))))))))) (VP (VBZ is) (RB not) (ADJP (RB so) (JJ intelligent))) (. .)))