Schools are facing a "tidal wave" of pupils with complex special educational needs the "likes of which they have never seen before", a government adviser warned last week.
Professor Barry Carpenter, associate director of the Specialist Schools and Academies Trust, said advances in medical science have seen a rapid increase in the survival rate of premature babies, leading to children with learning difficulties that have not been previously encountered.
The issue has been exacerbated by an increase in alcohol abuse among mothers during pregnancy that leads to foetal alcohol spectrum disorders, Professor Carpenter said.
"I like to sit in the staffroom during the first few weeks of term and wait for the day when one staff member says: 'I've never seen a child like this before' - and they are right," he said.
"It is happening time and time again. We are facing a tidal wave of children the likes of which we have never seen before."
Progress in medical science has meant children born at 24 or 25 weeks are staying alive and eventually attending school, when 10 or 20 years ago they would have died at 18 months.
The challenge for schools, Professor Carpenter said, was to develop new approaches to teach these children.
"These children are widely different, but we are educating too many 21st-century children with a 20th-century tool kit," he added.
Lorraine Petersen, chief executive of the National Association for Special Educational Needs, agreed with Professor Carpenter, adding that more needed to be done to train teachers to teach children with these learning difficulties.
"With an increase in disorders such as foetal alcohol syndrome, we are seeing more and more children with mental health issues," Ms Petersen said.
"I can't remember a child with mental health issues when I was a teacher.
"The white paper will not help with its plans to develop more on-the-job training. We need proper training to up-skill our teachers so we know how to deal with these children in the future."
Liz Sidwell, chief executive of the Haberdashers' Aske's Federation in south-east London, said schools needed to be more "professional" when it came to SEN.
"We have large SEN departments but they are usually filled with people who don't really know what they are doing.
"Although they are well meaning, we need to be more professional and better trained," Dr Sidwell said.
The Department for Education has called for contributions to a SEN green paper that is expected to be published in the new year. A spokesperson said: "All children with special educational needs and disabilities should have the same opportunities as other children, but we know that under the current system too often this doesn't happen.
"That is why we are looking at the whole SEN system."
Drink takes toll
According to the British Medical Association, foetal alcohol spectrum disorders (FASD) are a series of "completely preventable mental and physical birth defects" that result from alcohol abuse during pregnancy.
The disorder is believed to affect one in 100 UK-born children, with that figure rising due to an increase of binge drinking among young women.
The condition can affect numeracy, behaviour, and cognitive and social skills, but often goes unnoticed or misdiagnosed in schools in England.
Professor Carpenter is currently working with the Training and Development Association for Schools to better equip schools and teachers to recognise the symptoms of FASD, and to help teach them.