Young women earn 15% less than men even if they have similar vocational qualifications, according to a new report.
Research by the TUC found that men aged between 22 and 30 with a vocational qualification above GCSE level earn £10 per hour an average, compared with £8.50 for women.
The TUC said one of the main reasons young women earned less than their male peers was because they worked mainly in sectors where pay is poorer.
The analysis of official figures shows that in 2015, just one in 40 vocational qualifications in construction were awarded to women.
Women received 10.8% of vocational qualifications in engineering and manufacturing, compared with 63% in health and care.
TUC general secretary Frances O'Grady said: "Young women with vocational qualifications experience a huge gender pay gap.
"Many are still pursuing careers in 'traditional' industries that offer lower wages. Whereas in better-paid sectors like engineering and construction they remain a rarity.
"Unless we challenge gender stereotyping and discrimination from the outset, the situation is not going to improve."