Who wears the trousers?

A donor to UKIP has caused somewhat of a furore by saying that women shouldn't wear trousers because the Bible says that to do so is "an abomination".  So does it? Well, not exactly - in Deuteronomy (which is reputedly a record of the teachings of Moses) it does say “A woman shall not wear a man's garment, nor shall a man put on a woman's cloak, for whoever does these things is an abomination to the Lord your God".  But of course back then, trousers were unknown - men tended to wear either loincloths or loose robes.  So the question is - who decided and when that trousers should be "a man's garment"?  I think initially it probably came about as a matter of practicality -  if you're a woman, trousers are more difficult to cope with than a skirt if you need to go to the toilet - particularly as prior to the Victorian era, women tended to wear nothing under their skirts.  It wasn't until the 1920s (my Mum told me about this because it was her generation) that it became a fashion fad for young women to adopt masculine clothes, masculine names and masculine manners and it's gone on from there.  So what about Deuteronomy? Seems to me that it was aimed specifically at what today we would call "cross-dressers" - those who deliberately choose to dress as the opposite sex - rather than those who simply find a particular article of clothing practical and comfortable despite it being usually associated with the opposite sex.  And for that matter, what about the kilt???