Does gender stereotyping of instruments start in elementary school?

So I figured out my actual idea for my term paper for Women in Music.  Last week, Dr. Harold Abeles from Teacher's College of Columbia University came in for the day to present to the Music Education department.  The lecture he presented described his research on gender-crossing on instruments in public schools, (i.e., girls playing trumpets and boys playing flutes.)  As I had lunch with Dr. Abeles, I was fortunate enough to learn more about his studies and how, through a series of interviews conducted across 100 public schools (I'm pretty sure middle-high schools), he could quantify how many students were playing instruments outside of the 'norm' for their gender.
Most likely everyone knows this about me, but I fit into this "gender-crossing" stereotype.  I started playing trombone in 4th grade, and became a good musician because of it, possibly because now I was 'special.' (I was a dramatic middle-schooler, but that's another story.)

We saw reactions from adolescent boys and girls about gender-crossing instrumental performances. My question is- is that because all we have experienced are men playing trumpet and women flute, or could it be much deeper into a child's perception of music?  I could understand if people thought the trombone sounded masculine because it sounded "powerful", but then who is to say power is to be associated with men?

I am researching this topic in conjunction with my honors contract for Critical Pedagogy III this semester.  For Women in Music, I will be looking into what others have to say on the subject, besides Dr. Abeles.  For Critical Pedagogy, I will be conducting a small study with the students at my practicum site.

I don't think I've ever been this excited for a research project- it is not just that it is a topic I am interested in, or that I find applies to me; it's a topic I really want to know the answer to!

But I think I've found a 'niche'.  I just recently decided my goal for grad school is to get into Teacher's College, which I actually did not know Dr. Abeles was a member of the faculty until I looked it up for the benefit of this blog, and have been strongly considering studying this concept further.

:-)