These are among the conclusions of the latest report on the attainment of the city's five-year-olds. It revealed that the achievements of 2001-02 - when disadvantaged P1s made faster progress in reading and maths and were closing the gap on other pupils for the first time since early intervention began - have not been maintained.
The gap widened in 2002-03 and again in 2003-04, Anne Horgan, principal officer for education statistics, reported to the council's education committee on Monday.
While there have been significant improvements on average in reading and maths attainment since 1999-2000, the committee agreed to support further research aimed at improving the attainment of the most deprived children, and boosting reading scores among boys.
Aberdeen has taken the lead in assessing pupils at the start and end of P1 to gauge performance and the value added by the school, using the Performance Indicators in Primary Schools (PIPS).
Reading attainment at the end of P1 last session was higher than ever before, Ms Horgan reported, and many pupils are now nearing the maximum score. Performance in maths is also better than ever.
But the gap in reading attainment between disadvantaged and advantaged children in P1 widened in 2003-04. The report describes the gap as "significant" but says it is narrower than in 1999-2000 and 2000-01 - a PIPS score of 91.2 for those on clothing grants and 113.4 for the others by the end of P1. At the start of the year, the scores were 27.6 and 36.1 respectively.
The same picture emerges in maths, although children on clothing grants were only four PIPS points behind their peers at the end of P1 - the same margin as at the beginning.
The results reinforce continuing concern about boys' performance. Boys started off in P1 reading less well and making significantly less progress than girls and the same was true of those receiving clothing grants compared with others in the class.
"These effects added together mean that boys who are in receipt of a clothing grant have a double disadvantage in reading," the Aberdeen report states.
The good news for those struggling to improve boys' performance is that, while there was no significant difference in average maths scores of boys and girls in maths at the start of P1, boys made much faster progress and their average maths score had overtaken that of girls.
However, the advantage that girls have over boys in reading by the end of primary 1 is greater than the advantage that boys enjoy in maths.