The Talmud says ‘Kol Be-Isha Erva’. The direct literal translation of our sages in this case reads ‘A woman’s voice is her genitals’. Luckily, the meaning is not the direct translation, but it’s almost. The meaning is ‘a woman’s singing voice induces desire, and therefore is not allowed to be heard by men’.
The origins of this absurd rule are not necessarily the same as its current strict interpretation. It was probably aimed at some specific prayer (not that this meaning was somewhat more justified). Still, nowadays it has evolved to forbid any male Orthodox Jew to listen to a woman sings. It’s still ok to listen to a woman talks. Yay.
One wouldn’t really care that much about religious oddities, but it seems once you try to avoid them – they chase you wherever you are. The recent huge debate in the IDF (Israeli army) is not ‘how to tackle terror’ or ‘what to do with Iran’s nuclear effort’, but rather: Are male soldiers allowed to leave official ceremonies where and when women sing? The strongest and most modern army in the middle-east is developing high-tech anti-missile defense, but is afraid of songs. Perhaps this should be the new Hammas weapon at hand – it seems more effective in driving away soldiers, than the old fashioned ballistic pipes filled with explosives.
One should also research the unclear boundaries defined by modern technologies: Is a woman’s voice still forbidden if distorted by audio-processing software? Is a man’s voice ok if made higher in pitch by the same software? What about artificial text-to-speech results? Rest assured, there will be a good religious verdict for each. God’s taste in voices cannot be left to coincidence.