Below is a link to "Ask Hadley," Hadley Freeman's feature in the Guardian UK. Freeman is the only fashion journalist I know of who employs an actual sense of humour when writing about la mode. She's not afraid to take the piss when piss needs–demands!–to be taken, and, with fashion, that's most of the time.
The first bit is about Keira Knightley's odd photo look. Read, but continue on to the real gem, question 2: "Why don't boys wear dresses?" Not only is Freeman's answer spot-on, but this is how all answers should be given to three-and-three-quarter-aged questioners.
http://www.guardian.co.uk/lifeandstyle/2008/aug/25/fashion.women
(The photo, by the way, is from a fashion spoof site: The Dorcus Line.)
