The number of women in work has increased over the past 40 years, while men's employment has fallen, according to new research.
Around 67% of women are in employment, up from 53% in 1971, while for men the rate has slumped from 92% to 76%.
The Office for National Statistics said of the 13.4 million women in work, 42% were part-time, compared with 12% of the 15.3 million men in employment.
Men in full-time jobs worked an average of 44 hours a week, four more then women.
Most of the shift in more women and fewer men working happened in the 20 years to 1991, reflecting a decline in manufacturing and an increase in service sector jobs.
The increase in women's employment is partly due to more mothers working, leaving fewer not looking for a job.
Employment rates for women are lowest in Northern Ireland and London (both around 62%) and highest in the East of England, South West and South East (all around 69%).
Men tend to work in professional occupations with higher rates of pay, the research found, while the number of women in managerial roles was a third.
Daisy Sands, of the Fawcett Society, said: "While highlighting the strides women have made in the workforce over the last 50 years, today's report serves as a timely reminder of how far we have to go before we have a women friendly labour market.
"The analysis shows a consistently higher employment rate for men than women. Sadly, a great deal of this difference can be attributed to our old fashioned working practices, where combining paid work with other responsibilities is nigh on impossible. Women in the UK still tend to do the lion's share of childcare.
"Add to this the lack of flexible working opportunities and prohibitively expensive childcare, and we face a situation where for women, work all too often doesn't pay."
Dr John Philpott, director of The Jobs Economist, said: "While the UK jobs market has become much more feminised in the past four decades, with the employment rate gap between men and women narrowing markedly, judged by the types of work we do women have made far less progress.
"Whether due to employer practice or because women from their early 20s onward take on the bulk of child-care responsibilities, the persistence of gendered job roles leaves women at a relative disadvantage in the labour market."
TUC general secretary Frances O'Grady said: "The rising number of women in work has been the UK's biggest economic success story of the last 40 years.
"Yet women are still not being properly rewarded for the work they do. Women working full time still earn almost 10% less than male full-time workers, rising to nearly 40% for women working part-time.
"Too many women have to abandon their careers just to get flexibility in the hours they work. All too often the jobs in the sectors where women tend to work, such as the care sector, are underpaid and undervalued.
"We've come a long way but sex discrimination, unaffordable childcare, a lack of quality part-time work, and the undervaluing of women's work still cast a shadow over our labour market."
Business Minister Jo Swinson said: "Current workplace arrangements are old-fashioned and rigid. This is why the Government is introducing plans for shared parental leave and flexible working. These radical reforms will bring the way mums and dads balance their lives at work and at home into the 21st century
"Employers will soon get used to more men taking time off after their child is born and more mothers returning to work earlier, shattering the perception that it is mainly a woman's role to stay at home and look after the child. These measures will really help our aim of ensuring more businesses are making best use of women's talents throughout the organisation, from the boardroom to the shop floor.
"Shared parental leave also allows fathers to have greater involvement in the early stages of pregnancy and raising their child.
"In addition, the extension of the right to request flexible working to all employees will also help widen the pool of talent in the labour market, helping to drive growth."