First and foremost, "unisex" is an entirely loaded term. On the face of it, it's innocent enough, but in practice it's historically used as a way to turn women into second-class men. I went digging in the recesses of my mind (where it's usually not advised to tread, mind) as to when the term first arose, and I recalled that it was some time in the late 1960s. That said, precisely the only use of the term concerned attempts to get male-styles (be it clothes, hair, or whatnot) accepted on women -- I have never seen the term inverted to get women's style clothes (or hairstyles or anything else) accepted on guys.
If Wikipedia is to believed on the matter, the term was first used in 1968 in an issue of Life magazine. I found this interesting, as it dovetails quite nicely with my own memories (In 1968, I was seven years of age). Hilariously, the Wikipedia entry goes on to state, which I find completely apropro,
So, let's just discontinue the use of the term, shall we? It does us no good, and can be ultimately considered demeaning to our sisters.Eventually, the 1960s can be considered the decade in which “unisex” and “unisex clothing” became widely spread. The “unisex” trend arose in response to the youth revolution and the hippie movement of the 1960s and the women’s liberation movement of the early 1970s. However, this trend can be considered a more recent form of the aforementioned fashionable clothing, because it confirms a traditional feminine role subservient to the masculine role given the fact that “unisex clothing”, mostly, represents women wearing (altered) men’s clothing.