They say there is a worrying drop in the number of students choosing science-only A-levels - the people they hope will become the medical researchers of tomorrow.
As thousands of students consider their A-level options, the charities appealed for more consideration of medical research as a career.
They believe potential recruits are being lured away by lucrative posts in hi-tech industries. And they admit that medical career prospects are not helped by a public image of research as poorly paid, short- term employment.
Myc Riggulsford, spokesman for the Research for Health Charities group, said: 'We are desperate for more people to choose science. We fear there is a loss of confidence in science as a career. Yet these bright young people are required if we are to combat the more and more sophisticated diseases of the future.'
Royal Society statistics revealed that over the past few years the numbers taking science-only A-levels had fallen from 30 per cent to 25 per cent.
Mr Riggulsford said: 'This is a significant drop, given the increase in hi-tech jobs and the greater requirement for increased scientific knowledge.'
He believed students were being put off by the apparently hand-to-mouth existence of some researchers who constantly sought grant aid to maintain their projects.