The First Minister was accused of ignoring "mounting evidence" that the Scottish Government is limiting subject choice for youngsters as the issue was raised five times during the 45 minute question and answer session.
Interim Tory leader Jackson Carlaw raised the issue after report out this week from think tank Reform Scotland showed that pupils in their fourth year used to be able to study eight subjects, but that was now being reduced to six.
He said the Curriculum for Excellence was damaging young people’s future prospects and risked widening the attainment gap and added: “There is mounting evidence that pupils in s4 are experiencing a subject choice crisis – yet Nicola Sturgeon still refuses to accept this is a problem.
“Scotland was once famed around the world for the breadth of our education. But now, Curriculum for Excellence is narrowing horizons. Breadth as well as depth matters as do the choices available. We've been told the issue is Curriculum for Excellent and the Scottish Government is redrafting guidance again - third time lucky perhaps.
“Despite the best efforts of our teachers and the best efforts of our pupils, a whole generation is being let down on her watch.This is a massive failure of her government."
But Ms Sturgeon said the Reform Scotland study only looked at s4 while the senior phase of school covered three years. "What matters are the qualifications and awards people leave school with, not just those they study at s4," she said.
"We see the percentage of pupils getting qualifications at National 5 level is up and at Highers it is up. In 2009 the per cent of pupils getting five highers or more was 22 per cent - last year that was more than 30 per cent.. We have a record number of school leavers in higher education. The outcomes do not bear out Jackson Carlaw's analysis."
However the subject was raised again by Liz Smith a former teacher and Conservative education spokesperson, who asked what the First Minister would say to parents "who are concerned their child is only sitting six subjects while other schools are offering seven or eight with many feeling their youngsters are being disadvantaged in college and university applications?"
Ms Sturgeon reiterated that the "focus must be on the whole school experience. on the range of qualifications achieved, and the destination of young people when they leave school.
"What I would say to a parent is that the evidence says more young people going to university. including those from deprived communities, so the evidence suggests that contrary to her assertion we see the attainment gap closing."
Receiving support from SNP MSP Jenny Gilruth who also raised Curriculum for Excellence and said "pupils in Scotland study a broader curriculum for longer" Ms Sturgeon added: "We should listen to all views - in particular to those of a teacher which Jenny Gilruth was before she was in this Parliament.
"The evidence says that more young people are leaving school with qualifications, with five highers or more and going into positive destinations including university. I haven't heard any member of the opposition explain how that aligns with the analysis they're' putting forward."
But again Scottish Green MSP Ross Greer asked if she was concerned that the number of subjects on offer at higher level fell in more deprived communities.
She said: "If these things were creating the disadvantage that Ross Greer and others are suggesting, we wouldn't have the evidence that the attainment gap is at an all time low and the number from deprived communities going to univeristy is at an all time high."
And Scottish Labour's Johann Lamont, another former teacher, said she would suggest "the First Minister listens to teachers, parents and to the evidence from the experts telling us currently the system is more unequal than it was before and they are disturbed the evidence is suggesting the poorest are more disadvantaged than they were before."
But while the First Minister said she would "listen to views and evidence from wherever it comes", she again said that she would not ignore the statistics showing a record number of school leavers in higher education, and those from the most deprived areas up by eight percentage points since a decade ago.