A teaching union has called for selective grammar schools to be reintroduced across England.
Grammar schools have gone in most parts of England
Comprehensives and a "one-size- fits-all" policy do not deliver high- quality education, the Professional Association of Teachers heard.
Teacher Peter Morris said standards had fallen and discipline had worsened since the end of selective secondary education in most areas of England.
The PAT annual conference's vote will be referred to the union's council.
Mr Morris said: "We all have different strengths and weaknesses.
"Not everyone on this planet was born to be a brilliant academic. But there are some people in this country who are born to be brilliant academics.
"We must face up to the reality that children who are academically gifted should be given the same level of encouragement as those children who are slow learners."
Most 16-year-olds today would not gain good grades in the old O-levels, which were replaced in the 1980s by GCSEs, he said.
Mr Morris, from Bishop Gore Comprehensive School, Swansea, said: "Perhaps even more importantly standards of discipline have dropped with the introduction of comprehensive education.
"If a teacher spends too much time with low achievers then the high achievers become disruptive. The converse too is true."
Pupils in some parts of England - such as Kent - sit the 11-plus secondary school admission exam.
Opponents say this is divisive and elitist, but supporters argue that children learn best if they are placed with others of similar ability.
The PAT, which has 35,000 members, is holding its conference in Buxton, Derbyshire.