Children born using donated sperm and eggs will be able to trace their biological parents under plans announced by the government today.
The public health minister, Melanie Johnson, said that after a public consultation it had been decided that future donors of sperm, eggs and embryos would lose their right to anonymity.
Ms Johnson confirmed the move - which means that donor-conceived children will be able to find out the identity of their donor when they turn 18 - at the annual conference of the Human Fertilisation and Embryology Authority (HFEA) in London.
If the proposals get parliamentary approval, the new regulations will apply to children conceived after April 1 2005, meaning that the first time someone will be able to exercise the right will be in 2023.
The new regulations will not apply retrospectively, and - as is already the case -donors will not have any financial or legal obligations towards the child involved.
Ms Johnson's announcement prompted criticism from fertility experts who claim it will add to the current shortage of donors, making them less willing to come forward.
But support groups for people born using donor-assisted conception welcomed the decision, saying it would prevent them being denied important information about their backgrounds.
"I firmly believe donor-conceived people have a right to information about their genetic origins that is currently denied them, including the identity of their donor," Ms Johnson told the HFEA conference.
"There is a growing body of opinion, which I agree with, that donor-conceived people should not be treated so differently from adopted people. Today's new regulations will align their positions," she said, adding that the interests of the child had been paramount in her shaping the legislation.
To make sure that people still come forward to help infertile couples, the Department of Health also said it would be working to raise awareness of the need for donors. This will include funding a national helpline to provide information and support for people interested in donating sperm, eggs or embryos.
Ms Johnson also announced a review of the Human Fertilisation and Embryology Act - the legislation introduced in 1991 to regulate assisted conception - including a public consultation to start next year.
"Bearing in mind the speed at which new technologies in the fertility field develop and the complex ethical issues often associated with them, the Act has stood the test of time remarkably well," she said. "However, any cutting-edge legislation, no matter how successful, at some stage needs to be reconsidered and any necessary adjustments made to ensure that it continues to be effective."
Some 30,000 people undergo fertility treatment in the UK each year.
The review would be wide-ranging, but there was no intention to cover ground such as embryo research, stem cells and cloning that have been extensively and conclusively debated in recent years, she added.
The shadow health minister, Andrew Lansley, said he was opposed to the plans on the basis that they could undermine the future supply of donated sperm and eggs.
"The prospective benefit to some children who wish to know about their biological father or mother - which would in any case require highly sensitive counselling - must be weighed against the harm to couples wishing themselves to give positive parenthood to children of their own," he said.
The Project Group on Assisted Reproduction, Progar, which represents key organisations including the British Association of Adoption and Fostering and the Donor Conception Network, said Ms Johnson's announcement was a "forward-looking decision", which would benefit all concerned.
"Removing donor anonymity means that donor-conceived people are no longer the only group of people from whom the state withholds biographical information held on official records," said Progar's chairwoman, Elizabeth Wincott.
The decision to donate or use donor-assisted treatment should never be done lightly, she added.
"These are among the most responsible and long-reaching actions that anyone can take. We strongly hope that egg and sperm donors will now come forward, knowing that their donations will enable new families to come into being free of the stigma of secrecy."
But the director of the London Fertility Centre, Professor Ian Craft, said there was already a shortage of egg and sperm donors, and removing the right to anonymity would exacerbate the problem.
The head of development for Infertility Network UK, Sheena Young, said she had similar concerns.
"We worry that the removal of donor anonymity will only further the diminishing number of egg and sperm donors. There has been a decline in both sperm and egg donors in the UK over recent years and there are areas where the service has been in crisis for some time," she said.
