Just one in three young women believe both sexes have the same chance of success in their careers, a charity has claimed.
Women's confidence in this area plummets as they move from childhood to their early 20s, research for Girlguiding said.
A survey found 90% of girls aged nine or 10 think both genders have the same chance of succeeding in their chosen job, but just 35% of women aged between 17 and 21 feel the same.
The research suggested girls feel less proud, confident and powerful as they get older.
In an effort to boost confidence and inspire females, Girlguiding is running Camp CEO this week at Wyboston Lakes in Bedfordshire to mentor and provide expert career advice to teenage girls.
Girlguiding's chief executive Julie Bentley said: "This new research shows girls are lacking in confidence at an important stage in their lives when they are starting to think about the future, enter work or begin university.
"As the UK's leading charity for girls and young women it's our responsibility to change this through opportunities like Camp CEO - bringing together girls with successful female role models to fuel their ambition and build their confidence."
The research findings are from Girlguiding's Girls' Attitudes Survey 2016 and came from a survey of 1,627 girls and young women aged between seven and 21 from across the UK.