Academic entry requirements for medical degrees should be relaxed for students applying from the worst UK secondary schools, researchers say.
A study from the University of York says these students should be able to drop one or two A-level grades.
The study finds those on medicine courses with lower A-level grades do at least as well as their peers.
The Medical Schools Council said the research added "important data" to the entry requirement debate.
Competition for a place to study medicine in the UK is fierce, with about 11 or 12 applications made for each place on offer and entry grade requirements are high - at least AAA at A-level.
But the research paper says there is an over-representation of socioeconomically privileged individuals in the medical profession and that most of the schools that provide medical students are selective.
"It is known that 80% of UK medical students come from 20% of secondary schools and tend to come from economically advantaged backgrounds," it says.
The researchers gathered and analysed data from 2,107 students who started medical school in 2008 and grouped them into three groups:
- those with grades AAA
- those with AAB
- those with ABB or lower
They assessed their prior educational attainment and school background alongside performance on the United Kingdom Clinical Aptitude Test (UKCAT) and subsequent undergraduate knowledge and skills-related outcomes.
Their analysis found that those with lower A-level grades (AAB or ABB) from the worst secondary schools tended to have equivalent undergraduate performance to those from the best schools with top grades (AAA).
The study says: "Importantly, the findings suggest that the academic entry criteria should be relaxed for candidates applying from the least well performing secondary schools.
"In the UK, this would translate into a decrease of approximately one to two A-level grades."
'Able to keep up'
Lead author Lazaro Mwandigha said: "This study suggests that relaxing A-level grade entry requirements for students from the worst performing secondary schools is beneficial.
"Although there are important further questions about how to fairly classify schools, the study demonstrates that these students are, on average, just as able to keep up with the pace of a medical degree".
Supervising author Dr Paul Tiffin said: "This study is the first robust evidence that grade-discounting for pupils from underperforming schools is justified.
"At the moment around 20% of UK schools are providing 80% of our medical students, so A-level achievement should be viewed in terms of the context in which a pupil learns in order to help increase fairness and widen participation in medicine.
"The NHS needs more doctors from under-represented minority groups - having doctors from a wider range of backgrounds would enable health professionals to better understand and meet the UK's diverse healthcare needs."
What do medical schools say?
The Medical Schools Council says it monitors medical schools' performance on widening admissions.
Clare Owen, assistant director of the MSC, said: "This research adds important data to our understanding of how entry requirements relate to subsequent performance.
"The Medical Schools Council recognises the benefits of admissions which take applicants' backgrounds into account and this year published a guide which collects together the best practice of medical schools as they implement contextual admissions.
"Each medical school must decide on the best approach for its circumstances. And this research will help them by making a significant contribution to the evidence base."