The future of 12 primary schools in an area of Kent is being reviewed because of falling pupil levels.
Education officials said fewer births in Walderslade had already led to an 11% drop in numbers since 2001.
With that percentage predicted to rise still further, Medway's education authority admitted "removing school places" was a possibility.
However, it was stressed that nothing had been decided with regard to any school closures or amalgamations.
"We are at the very earliest part of the review," said John Farry, the education authority's planning and review manager.
"We're forecasting ahead now for the next five years, to 2009 to 2010, and we're expecting up to a 23% drop in pupil numbers.
"The number of births that we have which we monitor in the area, they've fallen significantly.
"Whereas in some areas of Medway that's been compensated for by new housing developments, there's been much less new housing in the Walderslade area."
Mr Farry said the review would take into account the possibility of pupil numbers rising again in the future.
"We'll be looking at schools which have particularly good sites and are large enough in capacity to expand if numbers demand it later on," he said.
He also addressed the issue of some parents possibly having to travel further if their child's primary school closed.
"We do have to be careful of that and we would need to be sure that congestion and car journeys were minimised."