Experts warned of a "looming national health crisis" as it was revealed today that one in three Brits born this year will develop dementia.
Alzheimer's Research UK said as people live longer, the numbers with dementia will rise.
The latest figures obtained by the charity show that 37% of girls born in 2015 will develop the condition in their lifetime, alongside 27% of boys.
The group called for investment in research to find new treatments and preventions in order to beat "our greatest medical challenge".
Dementia affects 850,000 people in the UK, resulting in the loss of brain cells. The most common type is Alzheimer's disease.
The latest analysis, commissioned by Alzheimer's Research UK and carried out by the Office of Health Economics, was released to mark World Alzheimer's Day.
Previous research from the same team estimated that the development of a drug which could delay the onset of dementia by five years would cut the number of cases by a third.
Dr Matthew Norton, head of policy at Alzheimer's Research UK, said: "It's wonderful news that each generation is living longer than the last, but it's important to ensure that people can enjoy these extra years in good health.
"Dementia is our greatest medical challenge and, if we are to beat it, we must invest in research to find new treatments and preventions.
"Research has the power to transform lives, and our actions now will help determine the future for children born today."
Amanda Franks, whose mother Cathy was diagnosed with early-onset Alzheimer's six years ago aged 58, said simply day-to-day tasks like making a cup of tea soon became a challenge for her.
Ms Franks, from Swindon, said: "Up until then, we had no idea this devastating disease could affect someone so young.
"As a mum myself, I would dearly love to see preventions and new treatments found to defeat Alzheimer's disease and other dementias, giving hope to people now and future generations."