There actually is a fairly longstanding theory behind the androgyny of the fashion industry: fashion's obsession with bony, prepubescent figures is driven by gay male designers, who are occasionally accused of wanting women to look more like boys.
Patrick Strudwick wrote an article in this weekend's Guardian refuting this notion. What I find most interesting is his argument regarding thinness. Strudwick says the fashion industry's obsession with thinness is commercial, not a secret agenda ginned up by gay male designers: "The way to extract money from someone is to encourage fear and the desire to control. Fear causes us to buy that which prevents social rejection, to be ahead of the Joneses — deodorant, the latest cut of jeans, the constantly upgrading gadgets. And controlling tendencies lure us to products that shape ourselves and our environment: the Ajax, the Ambi Pur plug-ins, the liposuction. A thin control freak is fashion's ultimate customer."
Transgender model Valentijn de Hingh