The impacts of both increases may end up being felt the most on the housing market. Rollin Stanley, the director of Montgomery County's planning department, says both populations will want similar housing over the next decade, though for different reasons.
"It should be telling the marketplace -- in places like White Flint, Silver Spring and Wheaton -- that there is a market potential here to provide smaller, more affordable units to a segment of the population in this county that is underserved," he says.
The traditional single-family home may be too expensive for the young adults still with their parents, while many of those about to retire will want to downsize, but not to an apartment or an assisted-living facility. Stanley says the housing market is slowly beginning to catch on.
"Ninety-seven and a half percent of our residentially zoned land is for single-family homes. We have a lot of them. What we need now is another housing product to grow," he says.
Over the past decade, the aging population grew so fast that it raised the median age in the county almost two years to 38.5.