Disturbing questions were raised by a rape conviction this month in Glasgow's High Court. A young man was convicted of raping a Scottish schoolgirl, not even a teenager at the time of the attack.

He was supposed to be babysitting and she had a baby as a result, which she gave up for adoption.

She was held up in many newspapers as a shocking example of young promiscuity and the failures of government sex education programmes.

But this story isn't an isolated one. In several previous cases, extremely young mothers have been vilified only for the true facts to later put a new perspective on events.

Are the details of these cases swept aside, uninvestigated or even sometimes suppressed, because of other moral and political agendas? And are these cases actually about failure to protect a vulnerable child?

Jason Middleton raped this girl at her home while she was in his care. The court heard she has since tried to commit suicide several times.

Unfortunately, rape and suicide attempts did not fit with what many people wanted to hear, because such girls become a perfect metaphor for everything allegedly wrong with our society.

Remarkably perhaps, nobody publicly raised the possibility of rape or longer-term abuse. She became at once the idle promiscuous product of sink-estate parenting and welfare culture, the permissive society and the crisis in our sex education.

People working with child protection and sexual abuse maintained that girls that young do not get pregnant unless after rape or sexual abuse.

They regularly deny it and invent a story through intimidation, shame or misplaced loyalty. Very early drinking, heavy smoking and school exclusions are also classic signs in abused children trying to blot out disturbing events. In my recent research study with men sexually abused as children, many were repeatedly excluded from school and a quarter were addicted to substances before reaching their teens.

Another clue is that often the stories in young pregnancy cases, published gullibly despite inconsistencies, do not stack up. These girls and families always claim it was one-off sex with a mysterious unnamed young teenager, in some drunken event.

First-time-ever pregnancies do happen occasionally, but they're rare indeed compared with the possibility that this had been happening for a while.

The young Scottish mum is not alone in her misrepresentation.

Jenny T, a 12-year-old mother from Dorset with learning difficulties, again from a family on benefits, was first said in 1997 to have tried sex with a 15-year- old boy at school. But, oddly, it later changed to "a night of experimenting with a 13-year-old boyfriend."

In 2002, Amy C from Sussex, also 12, became "Britain's most notorious gymslip mum" and "a national disgrace", facing moral outrage and abusive comment about promiscuous welfare chavs and the permissive society.

She claimed a one-night stand with a Jamaican boy, a visitor from London whose name she didn't know, at a leisure centre. This became a "club", then she later called him a Gambian boy (her child, publicly photographed, was black and she was white). No official action was taken.

Buried deep, however, in the text of these Press accounts is the news that Amy's mother had had a string of live-in boyfriends, her latest being a Gambian man with whom the mother had a baby. He had recently "returned to Gambia to his wife and children."

Was this man ever sought? Was his DNA checked? And if not, why not?

There was then national moral outcry about another (this time unnamed) pregnant Yorkshire girl of 12, with a mysterious young boyfriend.

Later, in small-print reports, her stepfather was charged with sexual abuse.

Many politicians, media and members of the public have thus shown a doublethink whereby everyone condemns child sexual abuse, but when very young girls show evidence of sexual activity they turn instantly into sluts and evidence of moral collapse. Often, reasons are then found to obscure the facts.

The next time a pre-teenage child gets pregnant, could we stop scapegoating her for political ends, and call for a thorough child protection investigation - instead of gullibly swallowing unlikely tales? Sarah Nelson is a specialist researcher and writer on child sexual abuse based at Edinburgh University.