More Generation Y, or Millennial, employees are stepping up into leadership roles, but older generations are reporting some unease when it comes to answering to younger managers.

Between 2008 and 2013, 87% of Gen Y managers surveyed by EY (formerly Ernst & Young) said they took on some kind of management role in the office, a recently recent report states.

The leading challenge cited across all generations was being uncomfortable with younger employees managing older workers (72%).

Dan Black, EY Americas director or recruiting, told Fox Business the number of Gen Y’s in managing roles had surged in the last five years, changing workplace dynamics around the world.

“This generation (Y) is large and ageing. There is still a misconception that millennials are fresh out of school, but they have been in the workforce for some time. They’re maturing and coming of age,” he said.

However, despite Gen Y’s stepping up to the plate, Gen X employees still come out on top when comparing characteristics and management skills, the report found.

Gen Xers were cited as the “best” of the generations in seven of 11 attributes, including being a “revenue generator” (58%), being able to adapt (49%), problem solving (57%) and being collaborative (53%).

Gen Y, on the other hand, scored lower for being “team players” (45%) and hardworking (39%) and 68% of respondents viewed them as “entitled”. However, the same number of respondents also viewed this generation as being “enthusiastic”.

Baby Boomers received the highest marks for being productive and the most-hardworking of the generations.

EY surveyed more than 1,200 professionals with responses from both managers and non-managers in the millennial generation (ages 18-32), Gen X (ages 33-48), and Baby Boomers (ages 49-67).