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)))) (. .)))
People who call someone whose sex is known a chairperson don't think about that.
( ( People ( who ( call ( someone ( ( whose sex ) ( is ( known ( a chairperson ) ) ) ) ) ) ) ) ( ( ( do n't ) ( think ( about that ) ) ) . ) )
(ROOT (S (NP (NP (NNS People)) (SBAR (WHNP (WP who)) (S (VP (VBP call) (NP (NP (NN someone)) (SBAR (WHNP (WP$ whose) (NN sex)) (S (VP (VBZ is) (VP (VBN known) (NP (DT a) (NN chairperson))))))))))) (VP (VBP do) (RB n't) (VP (VB think) (PP (IN about) (NP (DT that))))) (. .)))