More than a third of children aged six and seven in England are suffering stress because of the national tests they have to take, a survey suggests.
One in every 10 children is said to be losing sleep
The survey of 200 parents, carried out by YouGov for the Times Educational Supplement, found that by the age of 11, when they take their next set of national tests, two thirds were showing symptoms of stress.
A quarter had lost their confidence and a fifth were so busy revising they had less time to play with their friends.
On Thursday, the Education Secretary, Charles Clarke, told a teachers' union conference that tests in England were "here to stay".
He said politicians who wanted to abolish the tests - as Labour ministers in Wales have done for seven year olds - were living in "Alice's wonderland".
The survey suggested that one in 10 seven year olds were reduced to tears and lost sleep because they were so worried about the Sats tests.
Twelve per cent of 11 year olds had refused to go to school to sit tests and 9% had suffered anxiety attacks.
Margaret Morrissey, of the National Confederation of Parent Teacher Associations, said: "We really are in grave danger of taking their childhood away.
"Children are in school for a lot of the time. It will be really sad if they lose the time to play with friends when they are at home as well."
Teachers at the NASUWT conference, though generally giving Charles Clarke a warm reception, were less enthusiastic about his attitude to testing.
And earlier in the week, delegates at the conference of the biggest teachers' union, the NUT, voted to ballot members on a boycott of tests for seven, 11 and 14-year-old pupils.