Written by Lianne Kolirin, CNN

Gucci, Saint Laurent and Alexander McQueen are among leading fashion brands who have pledged to work only with models aged over 18.

Young men and women under that age will no longer represent the brands owned by French luxury group Kering from 2020 onwards, according to the company's chairman and chief executive Francois-Henri Pinault. The new guideline will apply to both fashion shows and photo sessions.

In a press release, Pinault explained that the move sought to inspire others within the industry. He said: "As a global Luxury group, we are conscious of the influence exerted on younger generations in particular by the images produced by our Houses. We believe that we have a responsibility to put forward the best possible practices in the Luxury sector and we hope to create a movement that will encourage others to follow suit."

The fashion industry is no stranger to controversy, having faced much criticism in recent years over its over the use of 'size zero' models.

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Two years ago, Kering and rival conglomerate LVMH -- which owns Louis Vuitton, Fendi and Givenchy, among other brands -- published a charter on models' well-being, which set the minimum working age at 16. It aimed to introduce a range of guidelines to safeguard the health and well-being of models, including a pledge to only employ models with a valid medical certificate.

These changes were introduced a month before Vlada Dzyuba, a 14-year-old Russian model, fell ill and suddenly died while working in China in October 2017. The tragic episode sparked a debate about underage models and their working environments.

But the new policy, which will come into effect in time for the Autumn-Winter 2020 collections, goes beyond that.

Russian model Vlada Dzyuba, 14, who died after taking part in Shanghai Fashion Week in 2017. Credit: Zhu jiahao/Imaginechina via AP

"In our view, the physiological and psychological maturity of models aged over 18 seems more appropriate to the rhythm and demands that are involved in this profession," Marie-Claire Daveu, chief sustainability officer and head of international institutional affairs at Kering, said in the company's statement.

"We are also aware of the role-model element that images produced by our Houses can represent for certain groups of people."