It's billed as the biggest change in sex equality legislation for 30 years.
On Friday, 6 April the Gender Equality Duty comes into effect, designed to proactively tackle policies and practices that look gender neutral, but can contribute to greater inequality.
Here we explain how it may affect you.
Doesn't equality mean women and men should be treated the same?
Women are disadvantaged by systems that just don't allow for their caring responsibilities, different patterns of working life, or greater vulnerability to domestic violence and sexual assault.
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For example, whilst transport routes are often designed with commuters in mind, they aren't always convenient for women who need to get to the doctors or hospitals, childcare or the food shops.
But men also miss out when workplaces don't recognise their family or childcare responsibilities, when family support services assume they have less involvement in parenting, and when health services don't take into account their different needs.
Men are less likely to visit their GP for example - and so diseases like lung cancer spread further before they are diagnosed.
Bradford's flagship Health of Men Initiative is experimenting with getting health information to men through pubs, barbershops, sporting clubs and mosques, environments where blokes are comfortable.
And the Gender Equality Duty also applies to transsexual men and women, at least in terms of employment and training.
And from the end of 2007 transsexuals are legally protected from discrimination and harassment by the recent European Directive on equal treatment.
So who's expected to follow this Duty then?
WHAT PUBLIC BODIES MUST DO
Gather information on how their work affects women and men
Consult all stakeholders
Assess impact of policies and practices on both sexes
Prioritise and set gender equality objectives
Plan and take action to achieve objectives
Publish a gender equality scheme
Review progress every three years
It applies to all public bodies, and a surprisingly large number of organisations fall into this category - from the Royal Air Force to the Victoria & Albert Museum, and most of the various arms of local and central government.
It can also apply directly to certain private or voluntary sector bodies who carry out public functions, like contracted prison management or privatised utilities.
It applies in a slightly different form in Scotland, Wales and England, though not in Northern Ireland which already has similar legislation.
Isn't this just a lot more paperwork, time and cost?
According to the CBI Public Services Directorate, "Public authorities need to look beyond rigid processes and ask how they can work with contractors to deliver better equality outcomes.
"Unnecessary bureaucracy could actually serve to hamper progress, something nobody wants to see."
What if I feel that I'm disadvantaged by my gender?
The Gender Equality Duty means the obligation is on public organisations to be proactive about equality - specifically by doing more in the way of consulting, assessing, formulating and implementing plans - and in general by thinking harder about equality and measures to address inequality.
But if you feel that the public sector organisations you interact with just aren't taking into account the differences between men and women, next month the Equal Opportunities Commission (EOC) will be putting template letters online that you can send to complain.
The current setup requires individuals to take cases to court; in future the EOC might be able to help.
And what if these public bodies don't take any notice?
It won't be acceptable for a public authority to claim it doesn't have enough resources to meet the duty - it's a statutory requirement and existing resources may need to be reprioritised to meet the duty.
At the moment, the EOC has what are called enforcement powers.
It can issue "compliance notices" - basically warnings - and can apply to the County Court for an order requiring public authorities to comply. And if they don't change their ways, they could be taken to the High Court.
However the EOC is currently due to disappear in late 2007, and a body called the Commission for Equality and Human Rights will take over responsibility for promoting and enforcing legislation on gender - along with similar disability and race duties.
So will the Gender Equality Duty really move the public sector to a golden future of equality?
KEY DATES IN LEGISLATION
1975 Equal Pay Act comes into effect (passed 1970)
1976 European Commission Equal Treatment Directive
1986 Sex Discrimination Act
2006 Equality Act
2007 Gender Equality Duty comes into force
The Public and Commercial Services Union, which represents some government service workers, is sceptical.
"We hope it doesn't go the same way at the Race Relations Amendment Act 2000, of which we had high expectations for change, but very little has changed for our members and users of public services," said a spokesman.
As organisations have three years to come up with plans and implement them, it may be some time before we see whether the Gender Equality Duty will improve public services for women, men and transsexuals.