Why, unlike authors, have there been so few female composers. Any explanations? Any ideas on what teachers could do to help improve the situation?

I am sure you are inviting musicians to discuss sexism and their own subject, but I would suggest that the issue goes beyond individual subjects (as you suggest yourself when you posted about the paucity of women artists elsewhere).

You might as well ask why, with the majority of teachers being women, are there far, far fewer women Headteachers than men? (Ditto politicians....Senior Social workers - again a role with the majority of ground workers female, but the majority of managerial people male).

According to the Guardian today 39% of secondary Headteachers are women, which is much higher than the number of women MPs (18%) and, unless the figures have changed, the number of women neurosurgeons (1%). Does this suggest that the teaching profession is the most egalitarian?
I have just started teaching about the suffragettes with my year 9s and I always start off by asking my boys to make a list of famous people in history - this year (as usual) they produced an entirely male list. I shall be liberating their patriarchal minds with a whole unit of women's history (of course that does not mean that this is the only time I look at women's role in his-story)

One of the main theories for a lack of female classical composers is that it is dependent on the public sphere. Whereas writing can be learned and practised in private, classical music composition requires a degree of professional training and traditionally involved formal employment (in court or church). These areas were closed to women until recently.

It is significant that female composers emerged during the folk boom of the 1950s and 1960s. Singer composers could appear in folk clubs on the same terms as men. The public for this kind of music, left of centre people who favoured sexual equality, were quite willing to be entertained by these singers. It was not long before some of these artists such as Joni Mitchell and Janis Ian entered the mainstream.

I suspect that when it comes to this kind of music composition, women are just as likely to be successful as men. I suspect there are still very few women classical composers (in fact it is a subject I know nothing about). It is said that there needs to be successful role models in existence for girls to be attracted to a particular profession. If there are any important women classical composers around, I would argue they should definitely be studied in the classroom. However, that probably reflects the fact that I teach sociology and history rather than music.

A good source of information on women composers can be found on the Music By Women website:

http://www.wrpm.net

Women covered include:

Hildegard of Bingen (1098-1179)

Caccini, Francesca (1587-1640)

Cozzolani, Chiara Margarita (1602-1678)

Strozzi, Barbara (1619-1664 c.)

Leonarda, Isabella (1620-1704)

Vizzana, Lucretia (1623)

de la Guerre, Elisabeth Claude Jacquet (1666-1729)

Grimani, Maria Margherita (1713 c. -1718)

Amalie, Anna (1723 c. -1787)

Von Martinez, Marianne (1744-1812)

Sirmen, Maddelena Laura Lombardini (1745-1818)

Szymanowska, Maria Agata (1789-1831)

Farrenc, Louise (1804-1875)

Mendelssohn, Fanny (1805-1847)

Lang, Josephine (1815-1880)

Schumann, Clara (1819-1896)

Chaminade, Cecile (1857-1944)

Smyth, Ethel (1858-1944)

Beach, Amy (1867-1944)

Mahler, Alma (1879-1964)

Clarke, Rebecca (1886-1979)

Seeger, Ruth Crawford (1901-1953)

Lutyens, Elizabeth (1906-1983)

Maconchy, Elizabeth (1907-1994)

Bacewicz, Grazyna (1909-1969)

Keal, Minna (1909-1999)

Gubaidulina, Sofia (1931-)

Rainier, Priaulx (1903-1986)

Williams, Grace (1906-1977)

Trimble, Joan (1915-2000)

Gideon, Miriam (1906-1966)

Boulanger, Nadia (1887-1979)

Tailleferre, Germaine (1892-1983)

Boulanger, Lili (1893-1918)