Boys get put unfairly in the bottom set for English by teachers who penalise them for having poor handwriting, inspectors said this week.
Schools fail to recognise the thoughtful contribution made to class discussions by able boys who are strong at speaking and drama but whose writing is seen as a weakness.
An Ofsted report on English, the first in a new series of subject studies, also found that pupils are being turned off reading by the assessment culture in schools.
The time spent reading for pleasure has declined and pupils increasingly see it only as a means to do well at school and get a job.
Despite these concerns, Ofsted praises English as one of the best taught subjects in both primary and secondary schools.
Teachers' subject knowledge, lesson planning and teaching of writing have all improved markedly in recent years.
But overall progress has slowed and about a third of primary teaching is still no better than satisfactory, insufficient to raise standards significantly and meet government targets.
Assessment was also criticised: "The quality of teachers' marking varies too much. At its best, marking is detailed, provides a personal response to what pupils write which helps to increase their confidence as writers, and clearly identifies specific areas for improvement. However, especially in primary schools, marking sometimes fails to tell pupils how they can get better and tends towards indiscriminate praise."
The report warned: "Few teachers take a wholly balanced view of pupils'
performance across the full range of English work in reading, writing, speaking and listening when assessing their work and determining ability groups.
"As a result, some able boys who contribute thoughtfully in discussion are not allocated to top sets in English because their writing (and, more particularly, their handwriting) is seen as a weakness."
Schools need to avoid damaging boys' confidence by having large numbers of them in low sets, inspectors said.
The report said the primary national strategy (formerly the literacy strategy) and the key stage 3 strategy have led to significant improvements.
However, it warned that some teachers lack the confidence to tailor lessons for individual pupils' needs.
"For too many primary and secondary teachers the objectives become a tick list to be checked off because they follow the frameworks for teaching too slavishly," the report said.
Pupils told inspectors that pressure to pass tests and hit government targets has reduced their enjoyment of English.
Teachers are uncertain how best to teach and promote individual reading alongside the new strategies.
The report said: "Is it appropriate or not any longer simply to read and share stories with their class; do they always need to analyse the text and set exercises? Is time for silent, independent reading regarded as good practice or not? Should teachers read whole novels with a class or is this a waste of valuable teaching time?
"In fact, Ofsted's evidence is that all these approaches, deployed appropriately, have potential, particularly as part of a systematic and balanced policy on reading."
Boys are more likely to give up on independent reading than girls and find it harder to find books to enjoy. The inspectors said teachers need to do more to keep up-to-date with books children will want to read.
Primary Forum 24 Letters 25 English 2000-05 is available from www.ofsted.gov.uk