Men who father children through sperm donation are to lose their right to anonymity, the government has announced.
Babies will be able to find out about their donor parent
The changes, which will also apply to egg and embryo donors, will come into force from April 2005, meaning the first time donor children will be able to find out their parent's identity will be in 2023.
However, the changes will not be retrospective.
Supporters say children conceived this
way have a right to information about their genetic parents.
But some fertility experts have warned many potential donors may be deterred if they could be identified.
The government carried out a two-year public consultation on what information donor children conceived should have access to.
Its recommendations were presented to the Human Fertility and Embryology Authority's (HFEA) annual conference.
Currently, under the 1990 Human Fertility and Embryology Act, children can be told if they were conceived using donor sperm, eggs or embryos at 18.
They can also ask if they are related to someone they want to marry.
The regulations will now be extended so that children can find out more biological information about the donor parent.
They will be able to have 'pen portraits' of their parent, which would detail their eye and hair colour and their occupation and religion.
Potential donors will be fully informed about the changes.
Health minister Melanie Johnson said they would have no financial or legal responsibility, and would not be forced to meet their donor child.
She said: "There is a growing body of opinion, which I agree with, that donor-conceived people should not be treated so differently from adopted people."
She told the BBC the government would be mounting an awareness campaign to tell people about the changes and encourage them to donate.
The 1990 HFE Act will also be reviewed to take into account developments in fertility technology introduced since it came into force.
Ms Johnson added: "Donors won't have responsibility, any more than they do now, for the financial or legal aspects of any children that are created. There is no change in that.
"The change will be that eventually a child might come forward and knock on the door, but we're hoping to set up a mechanism so it won't be a complete surprise to them."
Laura Spoelstra, chairman of the National Gamete Donation Trust, which raises awareness of the need for egg and sperm donors, told BBC News Online she favoured giving children more information.
Ms Spoelstra said: "It's like adoption. It helps some people who are adopted to know who their parent is."
Suzi Leather, chairman of the HFEA, said: "We have been asking for this for a long time. I can understand why people want to know who their genetic parents are."
Marilyn Crawshaw, a spokeswoman for UK DonorLink - a voluntary contact register for donors and their children, said: "This announcement has the potential to lift the stigma of secrecy from the field of donor conception."
But Sheena Young of the Infertility Network UK said: "We worry that the removal of donor anonymity will only further the diminishing number of egg and sperm donors."
Dr Allan Pacey of the British Fertility Society said: "The removal of donor anonymity will be of great benefit to the children born from donated sperm, eggs, and embryos.
But he added: "There is a danger that if we cannot recruit donors we may find that many infertile couples will be unable to receive treatment. We are concerned that if this happens, some couples may seek treatment overseas."