Her name is Ashley X, and she is the little girl who will never grow up.

Until New Year’s Day, not even her first name was known. Ashley was a faceless case study, cited in a paper by two doctors at Seattle Children’s Hospital as they outlined a treatment so radical that it brought with it allegations of “eugenics”, of creating a 21st-century Frankenstein’s monster, of maiming a child for the sake of convenience.

The reason for the controversy is this: three years ago, when Ashley began to display early signs of puberty, her parents instructed doctors to remove her uterus, appendix and still-forming breasts, then treat her with high doses of oestrogen to stunt her growth.

In other words, Ashley was sterilised and frozen in time, for ever to remain a child. She was only 6.

Ashley, the daughter of two professionals in the Seattle area, never had much hope of a normal life.

Afflicted with a severe brain impairment known as static encephalopathy, she cannot walk, talk, keep her head up in bed or even swallow food. Her parents argued that “keeping her small” was the best way to improve the quality of her life, not to make life more convenient for them.

Because of her small size, the parents say, Ashley will receive more care from people who will be able to carry her: “Ashley will be moved and taken on trips more frequently and will have more exposure to activities and social gatherings ... instead of lying down in her bed staring at TV all day long.”

By remaining a child, they say, Ashley will have a better chance of avoiding everything from bed sores to pneumonia — and the removal of her uterus means that she will never have a menstrual cycle or risk developing uterine cancer.

Because Ashley was expected to have a large chest size, her parents say that removing her breast buds, including the milk glands (while keeping the nipples intact), will save her further discomfort while avoiding fibrocystic growth and breast cancer.

They also feared that large breasts could put Ashley at risk of sexual assault.

The case was approved by the hospital’s ethics committee in 2004, which agreed that because Ashley could never reproduce voluntarily she was not being subjected to forced sterilisation, a form of racial cleansing promoted in the 1920s and known as eugenics (it was satirised in F. Scott Fitzgerald’s novel The Great Gatsby). However, the case of Ashley X was not made public, and, as a result, no legal challenges were ever made.

Ashley’s doctors, Daniel Gunther and Douglas Diekema, wrote in their paper for the October issue of the Archives of Pediatrics and Adolescent Medicine that the treatment would “remove one of the major obstacles to family care and might extend the time that parents with the ability, resources and inclination to care for their child at home might be able to do so”.

The paper inspired hundreds of postings on the internet: many supportive, others furious. “I find this offensive if not perverse,” read one. “Truly a milestone in our convenience-minded society.”

It was the critical comments that finally provoked Ashley’s father to respond.

While remaining anonymous, he posted a remarkable 9,000-word blog entry at 11pm on New Year’s Day, justifying his decision.

The posting includes links to photographs of Ashley, in which the faces of other family members, including Ashley’s younger sister and brother, have been blanked out. “Some question how God might view this treatment,” he wrote. “The God we know wants Ashley to have a good quality of life and wants her parents to be diligent about using every resource at their disposal . . . to maximise her quality of life.”

Ashley’s father went on to describe how her height is now expected to remain at about 4ft 5in (1.3m), and her weight at 75lb (34kg). Without the treatment, she would have grown into a woman of average height and weight, probably about 5ft 6in and 125lb, with a normal lifespan.

The medical profession is divided. “I think most people, when they hear of this, would say this is just plain wrong,” wrote Jeffrey Brosco. of the University of Miami, in an editorial. “But it is a complicated story . . . (But) high-dose oestrogen therapy to prevent out-of-home placement simply creates a new Sophie’s Choice for parents to confront.

“If we as a society want to revise the nature of the harrowing predicament that these parents face, then more funds for home-based services, not more medication, is what is called for.”

George Dvorsky, a director of the Institute for Ethics and Emerging Technologies, countered: “If the concern has something to do with the girl’s dignity being violated, then I have to protest by arguing that the girl lacks the cognitive capacity to experience any sense of indignity.”

• Dr Thomas Stuttaford tells why he supports the parents' wishes
• Ashley X: Are her parents wrong to stop her growing up?