More women than men are being denied the chance to work from home because of sexist bosses.
Figures published this weekend reveal that more than two-thirds of working mothers - 10 per cent more than men - complain that employers will not let them work flexibly.
Almost half of women also report a culture of rigid attitudes towards working hours.
Campaigners are warning that the findings, based on a survey by YouGov, show a huge gender gap in the workplace which penalises women who want children and a career.
Working Families, the charity which campaigns for a better work/life balance for parents, blames employers for failing in their legal responsibilities to working parents.
"Women who opt for a flexible plan are seen as less committed'," said Jonathan Swan, head of policy and research.
"Likewise, men are expected to be hands-on fathers and fit in to a 'long hours' culture."
Under EU laws, parents can ask to work flexible hours. But the research, commissioned by technology firm WebEx and based on a survey of more than 1,500 adults across the UK, found that nearly two-thirds of parents were ignorant of their rights.
The Equal Opportunities Commission (EOC) is also calling on ministers to widen access to parental leave for low-income fathers. Research published by the EOC reveals that men on lower wages still face barriers in taking time off around the birth of their child.