( This ( ( ( is ( uncommon ( in females ) ) ) ( because ( ( laryngeal ( growth spurt ) ) ( ( occurs ( commonly only ) ) ( in males ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ is) (ADJP (JJ uncommon) (PP (IN in) (NP (NNS females)))) (SBAR (IN because) (S (NP (JJ laryngeal) (NN growth) (NN spurt)) (VP (VBZ occurs) (ADVP (RB commonly) (RB only)) (PP (IN in) (NP (NNS males))))))) (. .)))
This is uncommon in females because laryngeal growth spurt occurs commonly only in males.
(ROOT (S (NP (JJ Female) (NN gender)) (ADVP (RB typically)) (VP (VBZ experiences) (NP (NN growth) (NNS spurts)) (ADVP (RB first))) (. .)))