A peculiar obsession with breast size as the test of true womanhood popped up in a French court last week, as the Chief Prosecutor in Nancy ruled that a transgendered woman couldn’t possibly be a woman unless her breasts measured up to size.

Argument is raging over the case of Delphine Ravisé-Giard, who first transitioned back in 2007. She is a long-term and serving member of the French Air Force – and the French Military had no problem recognising her new gender, in accordance with her own self-identification.

But she suffered a setback last year, when a civil court refused to accept that she could possibly change gender unless she undertook permanent and irreversible surgery.

There was better news in March of this year, when the Justice Minister rowed back from the previous requirement that an individual should actually have undergone reassignment surgery in order to gain recognition for their new gender. Rather, according to the Minister: “The principle of respect for private life requires that the state recognise gender according to a person’s appearance”.

He clarified this by adding that so long as an individual was en route to their chosen gender, via hormone therapy or other means (including cosmetic surgery), that should suffice. This brought France into line with the views of the European Commission on Human Rights for the recognition and treatment of transgendered individuals.

All should have been plain sailing, then: but the legal authorities in Nancy are making things difficult. The chief prosecutor simply moved the goalposts, acknowledging that the Justice Minister has spoken but now demanding proof of some permanent enhancement, such as breast augmentation or cosmetic surgery.

Ms Ravisé-Giard is predictably unimpressed. She told us: "If the state applied the same test to cis women [women born biologically female], it would have to redefine the gender of many French women. But of course, this would never happen."

She added: "What size breasts are required for a change in civil status? Will that breast size be established nationally by the Minister of Justice or will it be up to the personal tastes of individual attorneys?"

The case is likely to return to the French courts in the autumn.

The boob-kerfuffle français follows recent moves in Australia to ban pornographic material featuring small-breasted women, on the grounds that women in such pictures might not look like "proper women", and that therefore the pictures might encourage paedophiles – and similar moves in Germany to block publication of Hustler’s Barely Legal magazine on much the same grounds. ®