First we were given the duo scents, the "his" and "hers" versions. These scents for men and women go under the same name, have a similar bottle and a similar smell. The list is endless: Calvin Klein's Obsession, Eternity and Escape, Ralph Lauren's Safari, Paloma Picasso and Gianni Versace's Blue Jeans and Red Jeans. Only those with a sniffer-dog nose would notice the difference between the smells made for men and those for women.
So then we got daring: the bottles were shuffled, the labels were changed and, hey presto, confusion begins. Welcome to the world of unisex perfumes.
Those in the know about designer scents choose their perfume by its name, exclusivity and the lifestyle it offers, regardless of gender. Women sport Fahrenheit, Polo Sport, Kouros and Jazz - all designed for men. And men have been known to opt for the fresher female scents such as Issey Miyake, with the more extrovert chaps going for Jean-Paul Gaultier and Angel by Thierry Mugler. Traditionally, those men doing the "scent swap" would choose a light cologne such as Guerlain's Jicky, created in 1889 for women but sported by such beasts of masculinity as Sean Connery.
The new way, however, is that of one scent for all. It is a very Seventies idea and comes with the naff connotations of the sort of woman who wears a man's dinner jacket to cocktail parties. Except that the new concept is busy masquerading itself as impeccably modern.
Enter Calvin Klein and his new fragrance cK one (although, if the truth be known, Comme Des Garcons hit the British market first with a launch last Christmas of a unisex scent with an altogether richer, woodier feel). Klein developed the idea through observing his daughter with her friends; they swapped jeans, borrowed T-shirts; in his eyes, this was the "us" generation.
In theory, this a very sexy idea, living in perfect harmony with your partner with only one bottle on that bathroom shelf. But in practice, how boring. And just how sexy is it? The swapping of clothes is cute, but the sense of naughtiness lies in the fact that they belong to someone else. It is the same, surely, with scent.
Meanwhile, is your partner really going to be aroused by you smelling the same way? Whatever happened to sniffing out your future mate through the attraction of the senses?
cK one will be available from 21 August. Prices for body products start at pounds 13.50, the scent will cost from pounds 19.95.