Poor pupils are still missing out on studying three sciences at GCSE, say MPs.
Despite a huge rise in the numbers of youngsters taking GCSEs in biology, chemistry and physics, many are still not being offered this "triple science" option, said a report by the Commons Public Accounts Committee (PAC).
Evidence suggests students from the poorest areas are the most likely to be missing out, it said. The report also said pupils would begin to turn their backs on studying science if more specialist subject teachers were not recruited.
The cross-party group of MPs looked at take-up and achievement in science, as well as improving teachers and facilities.
The findings showed that the numbers of pupils studying separate GCSEs in biology, chemistry and physics (known as triple science when studied together) rose by almost 150 per cent between 2004/05 and 2009/10, while there had also been an increase in students taking A-level chemistry and maths. Take-up of A-level physics has risen more slowly.
But it added that 30 per cent of schools were not offering "triple science" in 2010, and cited research showing that it was less widely available in more deprived areas.
There was also a risk that the increase in take-up will not continue. Pupils' desire to continue studying science and maths depends on whether they enjoy the subjects and how well they achieve," it says.
Evidence shows that good teaching is "key to both enjoyment and achievement" but there are still not enough science and maths teachers with strong subject knowledge entering the profession.
"If the higher numbers of pupils taking science and maths are to achieve good results, they need to be taught by teachers with the specialist knowledge to teach these subjects well," the report noted.
PAC chair Margaret Hodge said the rise in availability and take-up was "impressive".
But she added: "The picture is far from rosy. Many pupils are still not offered triple science as an option, and those living in areas of high deprivation are most likely to be missing out."
The MPs also found evidence that science laboratories in many schools were not up to scratch, and even unsafe.