Parents not wanting their daughter to be touched (or even helped to the toilet) by the male teacher, female colleagues making "jokes" about pedophile leanings, and so on.
The divide in typically female and typically male professions is not a one-way street.
Of course music is easy to do blind this way. It isn't clear how you judge technical people in a fair way in a 5 minute audition. (see plenty of previous discussions here on white board coding)
Music also has high numbers of minorities going into it in the first place. The number of females who start a technical degree program is very low, and this is reflected in the graduations numbers (I understand females are more likely to drop out of the program as well, which needs to be addressed)
Failing that, what lawyers have done is a possible answer.