According to a report by the Institute for Fiscal Studies (IFS), only a quarter of young middle class professionals are on the housing ladder, compared to two-thirds in the 1990s.
And the figures are a stark warning for Mrs May, with Tory MPs urging her to take radical action.
They fear Mr Corbyn is using the issue to lure more young people to the Labour cause, giving him the upper hand at the next election.
Conservative MP Nick Boles warned: “The double whammy of stagnant wages and spiralling house prices has had a devastating effect on the ability of people in their 20s and 30s to but their own home.
“This is an iceberg warning for Theresa May and the Conservative Party.
“If we do not take bold steps to get more houses built it will sink us at the next election.”
The IFS said, in 1995/96, 65 percent of 25 to 34-year-olds on incomes falling into the middle 20 percent bracket for their age group were home-owners.
But by 2015/16, just one in four (27 percent) of this group owned their own home.
The IFS said this group of young adults is made up of those with after-tax incomes of between £22,200 and £30,600 per year, including any money coming in from a partner.
A third are university graduates, three-quarters live with a partner and around 60 percent have children.
Andrew Hood, a senior research economist at the IFS and an author of the report, said: “Home-ownership among young adults has collapsed over the past 20 years, particularly for those on middle incomes.
“For that group, their chances of owning their own home have fallen from two in three in the mid-1990s to just one in four today.
“The reason for this is that house prices have risen around seven times faster in real terms than the incomes of young adults over the last two decades.”
Average house prices were 152 percent higher in 2015/16 than they were 20 years earlier after adjusting for inflation, the report said.
By contrast, the real net family incomes of those aged 25 to34 have increased by only 22 percent over the same period.
Housing minister Dominic Raab MP said: “Through schemes like Help to Buy, we’re helping more people onto the housing ladder.
“Last year saw the highest number of first-time buyers in the UK since 2006.
“But we want to go further and faster and our ambitious plan backed by targeted investment will help even more people by delivering the homes Britain needs for young families, key workers and those on low and middle incomes.”