ReutersNew guidance for public bodies on single-sex spaces will be issued, after the UK Supreme Court unanimously ruled a woman is defined by biological sex under equalities law.
The Equality and Human Rights Commission (EHRC) says it is "working at pace" to provide an updated code of conduct for services, including the NHS and prisons.
The ruling could have implications for spaces such as hospital wards, changing rooms and domestic refuges.
The case was brought by women's rights campaigners who challenged the Scottish government, arguing sex-based protections should apply only to people that are born female.
On Wednesday judges ruled that when the term "woman" is used in the Equality Act it means a biological woman, and "sex" means biological sex.
This means a Gender Recognition Certificate (GRC) does not change a person's legal sex for the purposes of the Equality Act.
The Supreme Court justices argued this was the only consistent, coherent interpretation.
Baroness Kishwer Falkner, chairwoman of the Equality and Human Rights Commission, said the organisation was "pleased" the judgment addressed "difficulties" it highlighted in its submission to the court.
There is already Equality Act guidance which allows for women-only spaces, such as toilets, changing rooms and hospital wards in certain circumstances.
But under the new ruling a person who was born male but identifies as a woman does not have a right to use a space or service designated as women only.
That includes transgender women who have legally changed their gender and hold a GRC.
The equality watchdog says it expects its updated guidance to be in place by the summer.
The new guidance could also have an impact on women's sport, where the question over whether transgender women can participate has been a high-profile issue in recent years.
Sports have tightened up rules around transgender athletes at the elite levels. Athletics, cycling and aquatics have banned transgender women from taking part in women's events.
Other sports have put in place eligibility criteria. Earlier this month the English Football Association introduced stricter rules, but still allowed transgender women to continue to compete in the women's game as long as their testosterone was kept below a certain level.
Scottish Green MSP Maggie Chapman, a prominent campaigner for trans-rights, said: "This is a deeply concerning ruling for human rights and a huge blow to some of the most marginalised people in our society.
Trans rights campaigners have said they will be examining the judgment closely to decide on their next steps.
The UK government has welcomed the "clarity and confidence" for women and service providers brought by the judgement.
Health minister Karin Smyth said the government would be reviewing the ruling to "make sure we are fully compliant with it" and would be working with equality bodies to make sure organisations were fully compliant.
She said the government was not interested in "so-called culture wars" and believed that everybody should have "their dignity and privacy and their rights respected".
"I think now is the time to make sure that we look to the future, that rights are very clear for people and that service providers absolutely make sure they comply with the law," she said.
