Mr. Slimane has never officially designed for women, although his sleek male tailoring has dressed the famous of both sexes, including Nicole Kidman. Since he left Dior Homme five years ago to concentrate on his passion for photography, he has not been part of the fashion calendar.

Does the return of Jil Sander to her eponymous label this season and the hiring by the Ermenegildo Zegna men’s wear group of the former YSL designer Stefano Pilati suggest that androgyny is back in favor?

Not since the 1980s have there been leading designers so focused on tailoring. It would theoretically be possible, if unlikely, for either of the new protagonists at Dior and Saint Laurent to come up with a “girly” look. As both houses are guarding their doors with the secrecy usually reserved for a royal wedding dress, no hints have been given about what will seen on the runway this week at Dior or Monday at YSL.

Is this such a stand off after all, given that both designers are linked to men’s wear; both work as fashion purists, rather than decorators; and both are fascinated with youth culture and contemporary art?

Fashion has always thrived on the clash of titanic opposites. A famous sketch by Jean Cocteau in 1926 shows an elaborate outfit from Paul Poiret slinking off as the clean silhouette of Coco Chanel dominates the foreground.

Not much later, Mademoiselle Chanel was trading insults with Elsa Schiaparelli, whose whimsical and witty designs were the antithesis of the Coco graphic rigor.