MPs have called for reforms to remove "perverse incentives" for students to take dumbed-down exams at school.
Exam boards competing to attract business should be stripped of their right to decide the content of examinations sat by pupils aged 15 to 19, according to the cross-party Education Select Committee.
In a report published on Tuesday, the Select Committee calls instead for the introduction of national syllabuses to prevent boards bringing down the quality of exams as they fight for market share.
These national syllabuses for GCSEs and A-levels would be accredited by Ofqual, the qualifications regulator.
Graham Stuart, the Tory chairman of the committee, said there was a need for change due to "grade inflation" in recent years, which he said had led to a loss of faith in the examination system.
He said: "There is a combination of better teaching, better prepared pupils, harder work, but also there has been a change on grade boundaries and on the content and accessibility of the curriculum and syllabus, and that is why we suggest change.
"The public, employers, universities all need to have their confidence restored.
"A move to national syllabuses can provide exactly that change without massive disruption to the system, retaining the diversity and dynamism of multiple exam boards but getting rid of the perverse incentives to lower standards over time."
The report comes after Government plans to scrap GCSEs and replace them with "explicitly harder" O-level style exams were leaked two weeks ago.
Teaching unions and education experts claimed this would lead to a two-tier education system, but Education Secretary Michael Gove has since said he wants to move towards a one-tier set of high quality qualifications.
Commenting on the debate, Stuart said: "The Government has refused to say what its exact plans are.
"The Secretary of State has said he will make no further decisions until he has seen our report, which does not look particularly at the qualifications that are sat.
"It looks at the way they are administered and the way that impacts on quality.
"We, like the Secretary of State, want to move to a system which is right for every child.
"We don't want to see anybody turned into a loser at age 14, we want a system which brings out the best in everyone."
The committee's report, which suggests there should be a pilot scheme to test its recommendations, will now be considered by the Government over the next two months.
A Department for Education spokeswoman said: "All the evidence from parents, the best schools and our leading universities is that we need fundamental reform of GCSEs and A-levels so that they are rigorous and match the best in the world.
"We have already announced changes to GCSEs by tackling the resit culture and ending the modular structure, as well as introducing marks for spelling, grammar and punctuation for key subjects.
"And we have listened to concerns raised by academics at our leading universities on A-levels, and launched a consultation.
"We want to see every student in this country able to take world class qualifications, we want to tackle the culture of competitive dumbing down, and we want a curriculum which prepares all students for success by broadening what is taught in our schools and then improving how it is assessed."