I think girls are more motivated by social acceptance. I have two girls, they want to blend. I would guess that generational bias has to do with recognizing gifted girls. I would guess a "younger" teacher would be more aware of gifted traits in girls than an "older" one.
As a side note, I worked in investments and purposely lowered the tone in my voice when speaking in "work" situations. Not so much that I sounded like a freak, of course!
But I definately felt I was "listened" to more if I did this.

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