Sentence:  One growth center in a short bone - distal phalanx of the second finger - was chosen as an example for discussion here , primarily because epiphyseal diaphyseal fusion , the maturity indicator for Completion in long and short bones , occurs in this center for girls near the menarche and for boys near their comparable pubescent <WSD>stage</WSD> . 
Meaning of the word marked with <WSD> tags:  a specific identifiable position in a continuum or series or especially in a process