Okay, here's a crack at your questions. I hope my answers make sense to you - they are based on 32 years of living each and everyday believing that my gifts of communicating something about what it is like to be alive by organizing sound in time and space makes me a composer. That's what composing is - organizing sound in time and space - and in my case I do this in order to communicate something about what it is like to be alive. So that's the perspective of my 32 years (so far) of professional work. 

During these 32 years I've been working away in my own voice afloat in the myriad of several musical trends including Serialism, Atonality, New Romanticism, New Complexity, Minimalism, New Sonicism, the International Style, Brutalism, Post-Modernism(in the world of abstract classical music) and Rock and Roll, Rock-a-billy, Hard Rock, Heavy Metal, Punk, Techno, Hi-Hop, Rap, Ska, Reggae, Rock Steady, Bee-Bop, Free-Jazz, Big Band, and many, many more as we all know.

All of these are ways of organizing sound in time and space in order to communicate something about what it is like to be alive. What's interesting is that there is an attendant need in our culture to categorize music often and minutely. The question is why? 

It seems we possess and essential need to talk about music, as globally over thousands of years we have needed to talk about music. Yet in our culture we have no common-man vocabulary to discuss music itself, and so we try to talk about it by examining the things around it: what are lives of the people who write it like, what are the people who listen to it like, can we categorize the people who listen or DON'T listen to it? And similarly, when we do have vocabulary to talk about music, words such as dissonance and consonance are used most commonly in relationship to "like" or "dislike" or "proper" and "improper" - all sociological value oriented definitions. 

Now I know your questions have to do with the lives of women composers. And I'm assuming you are referring to composers who are trained in instrumental art music notation.  You've noticed that its difficult to hear live performances of abstract classical works composed by women.  And you've noticed (I'm assuming) that media tells us that the situation has "gotten much better" for hearing this repertoire, but in reality its appears not to have gotten better, and perhaps its gotten worse over the past decade.

Having by choice spent a great deal of my time and efforts composing works for orchestral instruments developed in the 1800's, I feel your pain.  The repertoire for these instruments has narrowed, perhaps even atrophied, over the past 20 years to be certain. Orchestral programming is the least innovative it has ever been in its entire history.  I bring this up as the focal point to your answer because the orchestra (not the chorus, not the wind ensemble) is the principal goal of youth orchestra, chamber music and conservatory training.  Courses of academic study, studio performance techniques, programming of concerts, programming of public radio, bin categories in record stores, the top ten classical music list in the 2002 Town and Country Magazine, everything having to do with notated classical music is one in the communal body of the 18th and 19th century orchestra. 

Here's the problem

1) -to learn to compose at a world class professional level for these instruments a young composer must be able to pass the entrance exams of a fine conservatory. These exams favor students who are trained on orchestral instruments - and these days are also trained in technology. I've noticed that historically the pool of entry for young women composers often comes through the vocal world or the performance art world.  These worlds are quite different in their training than the orchestral instrumental world.  So quite often a terribly gifted young composer, female, who has been able to find her compositional voice through performance art or song is excluded from study in college by dint of the entrance exam. The problem is exacerbated by the world fact of male designed and dominated technology. Its becoming a well-known fact that in school girls are encouraged to defer their learning time on technology to boys and boys are generally hogging the school computers nation-wide. Ergo girls find other outlets, ergo they form only a smallpart of the technological pool of student composer candidates.

The same is true, by the way, for terribly gifted young composers who have trained in garage bands, gospel choirs, and until recently, jazz bands. I've been asking my colleagues who hold academic positions if they account for either vocal or fret-board theory in their entrance exams.  They do not.  Hence the pool of  entry for young composers is severely limited by the ability of the academic institution to recognize their talent and train their passion to mastery. 

2) - composers need, and have always needed, strong, consistent and true champions of their work.  Historically these champions are conductors, performers and patrons.  Women have been steadily learning how to find and maintain artist/champion relationships, but it really only has been the last 20 or so years that our society has allowed itself to accept female/male-artist/champion relationships in which the artist is the female, the champion is male and the relationship is about the work and nothing more. Curiously, skepticism about this kind of a relationship seems to come more from women than men. Maybe its because 1000 years of conditioning is hard to release....

3) - in our culture, to succeed in maintaining a consistent public platform for one's artistic work, an artist must learn business skills and practice them respectfully and dispassionately. Music schools traditionally neglect teaching business skills as part of their curriculum, so students must come by their business knowledge in other ways.  Mostly by asking and asking questions until one gets the answers. It's the business skills that are much more available now to young women than they have been in during the last two generations. There are many more business mentors for young women now than there were when I was in my twenties, and of course there were more for me than for my mother's generation.  Not so for my grandma's generation! The women of those generations learned business skills (bookkeeping, accounting, commercial writing, negotiating, inventory control, management skills, project management)

4)- the orchestra, opera, chamber music business in our culture is suffocating in general because as a field its has no research and development mentality. The classical music performance industry has adopted corporate structure as its working model with one glaring, perhaps fatal, omission- no research and development.  Product rejuvenation, innovation, new product, all the things which help industry to grow (for instance 3M, or more close to home Broadway who brought in Julie Taymor to design the Lion King)are missing from the classical music industry.  Does this hurt the programming possibilities for up and coming young women composers - you bet it does! Will talented young women (or men) composers be compelled to give their best work to an art form which has no curiosity about what they have to say.  I doubt it. 

5) Finally, and perhaps most importantly, notated composition from which we are descendants was invented and evolved in monasteries. At its heart it's a monk's art-form, and its teaching practices have been handed down from that perspective.  Also its archival system is a monk's archival system. I'm not sure if its still true, but in the 70's and 80's, if a student wanted to look up a woman composer in the library system, she could not be found by name under the category "composer". Instead the student had to look under "woman - composer".  Strange, but true.     

The tragic part of all of this is that if its true that any composer working in any genre organizes sound in time and space in order to communicate something of what it is like to be alive, then in our world of instrumental "classical" music we are missing out on most of the vigorous, truthful and passionately talented voices our time - and in not performing music composed by women we have missed out entirely on what half our population has to say to us through music.