A-level results published on Thursday show that more exams were passed than ever before - with more achieving grade As.
The pass rate for A-levels is creeping closer to the 100% mark, increasing by 1.1 percentage points to 95.4% this year.
Head teachers say the rate is being fuelled by pupils' switching from maths and science to supposedly easier subjects such as psychology and media studies.
But the claims were rejected by the School Standards Minister, David Miliband, who said the results reflected the hard work of children and their teachers.
"Today is an important day for many pupils and they should be proud of their efforts," he said.
"Every A-level subject meets rigorous standards and several international panels have shown this in the past.
"Today is the day we should be celebrating not falling for the British disease of knocking success."
The A-level figures are released for the main exam boards in England, Wales and Northern Ireland by the Joint Council for General Qualifications.
They show a trend away from subjects such as maths, modern languages and science towards subjects such as psychology and media studies.
John Dunford, the general secretary of the Secondary Heads Association, said children were choosing subjects they thought were easier.
"The rise in interest in psychology is a consequence of what
people are perceiving, that maths and physics are harder and they can get better
grades in psychology," he said.
"It is easy to show that psychology is an easier A-level than maths. It is
incredibly worrying because maths and modern languages are subjects that the
He said the other reasons behind the rising pass rate were that weaker students dropped subjects if they did not do well in them at AS-level, and that children were working harder.
More A grades
The proportion of entries getting grade As is up 0.9 percentage points from 20.7% to 21.6%
In 1970, the figure was 8.9%.
George Turnbull, from the Joint Council for General Qualifications, told BBC Radio 4's Today programme pupils were more likely to get grade As if they took subjects such as maths, sciences or foreign languages - because proportionally, more were awarded in those subjects.
"If you are good at your subject, you will do well in it. If you are not, you won't," he said.
He also rejected the idea that some A-levels are easier than others: "Was Einstein better than Shakespeare? How do you compare?"
As hundreds of thousands of teenagers open the all-important envelopes to get their results, the exam authorities say students can be confident the results they get are fair.
Pass rates have risen markedly
The grading system was scrutinised and tightened after last year's A-level fiasco.
Some schools had claimed that students had been marked down to stop grade inflation and to counter accusations that A-levels were getting easier.
Mike Tomlinson, who carried out the inquiry into what went wrong with last year's A-levels, says he is satisfied the system has worked well this year.
"I have observed this year's awarding process at AQA, Edexcel and OCR and am satisfied that students can be confident that it has been conducted properly," he said.
"The recommendations I made last year have been taken on board."
At AS-level, there has been a fall in the proportion of entries getting the top grade. It is down from 18% to 17.4%.
But the proportion passing AS-levels is up 0.2 percentage points from 86.5% to 86.7%.
A-level pass rate 95.4%
up from 94.3%
750,537 A-level entries
701,380 last year
AS-level pass rate 86.7%
up 0.2 percentage points
Just over 1m entries for AS-levels - up 35,515
Girls' pass-rate 96.4%
Boys' pass-rate 94.3%
The figures are for England, Wales and Northern Ireland and are provisional - they could change slightly as a result of late entries and appeals.
The pass-rate for Wales as a whole is 96.4%, a rise on last year's figure, which was 95.8%.
In Northern Ireland, the picture is similar. The pass-rate is 97.2%, compared with 96.4%.
Students get their individual results on Thursday. The school-by-school "league tables" are issued towards the end of the year.
As a whole, there were more AS and A-levels this year than last, although this is not surprising as the number of 17 and 18 year olds is greater too.
Across the UK, there was a 7% increase in A-level entries, from 701,380 in 2002 to 750,537 this year.
The numbers taking AS-levels rose 3.6%, from 995,404 to 1,030,919.
Vocational A-levels seem to be growing in popularity, with 40,914 entries this year, compared with 32,246 last year.
Subjects covered include travel and tourism, IT and business.
The pass rate for vocational A-levels is also up - from 78.7% last year, when they were introduced, to 83.3% this year.
Boys improved their performance on last year, but girls improved at an even greater rate, maintaining the gender gap in results.
At A-level, girls increased their lead over boys from 2002 to 2003, in terms of whose entries get the most A grades, by 0.3 percentage points.
The pass-rate for girls' entries in the UK is 96.4% this year, while the rate for boys' is 94.3%.