The fact that almost 70 percent of young people expect to get an inheritance may mean they're in for an unpleasant surprise, since only 40 percent of their parents plan to leave one. That's according to new research from the Natixis U.S. Investor Survey.

The research shows that the under-35 set may need to question their assumptions about retirement and how to fund it: "Millennials say they plan to quit working at age 59, on average, a full six years earlier than Baby Boomers, who expect to retire at age 65." To help make that possible, they're hoping for a windfall.

Unfortunately, it seems, many of them are going to be disappointed.

According to Natixis, "44 percent of Boomers don't have a will; over half [57 percent] don't expect to have money left to pass on," whereas "another 35 percent plan to spend whatever money that's left on themselves."

Meanwhile, 24 percent of Boomers expect that "contributions from children" will play an important role in funding their retirement. No word on whether, or how, millennials are anticipating handling that expense.

Is this a failure of communication or of planning? Perhaps both. No one, after all, looks forward to awkward conversations about money or about death and its ramifications.