They explain that the orchestra forbids membership to women because they take too much sick leave. I quote here the salient points from the letters, and can fax or mail the originals, which are on Vienna Philharmonic letterhead, to anyone interested. In a second letter they explain this is because women are too often on sick leave. They write that the Vienna State Opera and the Vienna Philharmonic are drawn from the same pool of 149 musicians who rotate between the opera and the philharmonic. The Vienna Philharmonic, however, is a private club, which it has been since 1842, and thus these laws are not applicable.
Women commonly face such discrimination in German and Austrian orchestras.
At my last count the Berlin Philharmonic had 121 men and 3 women. The Czech Philharmonic also categorically forbids membership to women. These orchestras stand as national symbols for their countries, and represent western culture through out the world. I posted a notice about these letters on the net and it was forwarded to the Horn-List. Prof. Hans Pizka, principal horn of the Munich State Opera, responded with a defense of the orchestra's discrimination.