The Government's new English Baccalaureate has been attacked by MPs, who warned it was rushed and risks "shoe-horning" pupils into taking inappropriate qualifications.
Ministers should have waited until after the current review of the national curriculum was completed before introducing the so-called EBacc, the Commons Education Select Committee suggested.
In a new report, the cross-party group of MPs raised concerns at the speed at which the measure was introduced, as well as the possible impact on pupils from disadvantaged backgrounds.
The prescription of the EBacc does not cater for the differences between pupils, and could result in some being forced into taking subjects that they are not suited to, it warns.
The EBacc is awarded to teenagers who score at least C grades in English, maths, science, history or geography and a modern foreign language at GCSE.
Education Secretary Michael Gove introduced the EBacc at the end of last year, and the measure is now included in league tables - allowing schools to be rated on the proportion of their pupils achieving the benchmark.
The move proved controversial, as headteachers, schools and subject organisations raised concerns that they had not been told about the new measure in advance, and that subjects such as religious studies had been left out.
The committee's report says it understood the Governments wish to introduce reforms quickly, but said it "regrets the launch of the EBacc before the curriculum review was completed".
Schools minister Nick Gibb said: "We believe very strongly that all children have the right to a broad and balanced education that includes English, maths, science, a language and a humanity.
"These academic subjects reflect the knowledge and skills young people need to progress to further study or to rewarding employment. It cannot be right that children from the poorest backgrounds are significantly less likely to have the opportunity to take GCSEs in these subjects than children from more advantaged areas."