A consultation paper paving the way for changes to the Human Fertilisation and Embryology Act is set for publication in the next few months, a Department of Health spokeswoman confirmed yesterday.
With in vitro fertility treatment (IVF) using donated sperm or eggs now accounting for 2,000 births a year, the issue has become a priority for ministers, according to a Sunday newspaper. They believe it is wrong to deny these children facts about their genetic mothers and fathers.
But fertility groups warned that removing the right to anonymity would reduce the number of people prepared to donate sperm or eggs and threaten the availability of the treatment.
In particular it is feared that younger potential donors would be put off by the prospect of a surprise son or daughter turning up years afterwards.
"This may be a victory for children, but it certainly is not for the donors," said Tim Hedgeley of the National Fertility Association. "Their rights have to be protected too. People already give for altruistic reasons and now they are going to be hammered for it."
Himself a sperm donor, he said he would not have given without assurances of anonymity and quotes the experience of Sweden, where similar reforms led to a short-term decline in donors. Other experts said that in New Zealand donations fell by 90 per cent when similar changes were introduced.
The British proposals are due for publication this autumn, but it is understood that any changes made as a result would not apply retrospectively. The health department spokeswoman added: "This is only the first step on the way towards possible legislation."
The consultation paper is expected to push for similar rights to those granted to adopted children in the 1970s, when for the first time they were allowed access to information about their genetic parents on reaching the age of 18.
Childless couples seeking access to IVF treatment already face severe shortages and long waiting lists. Some hospitals have applied to import sperm from abroad, while others are offering cheap fertility treatment to women willing to donate eggs for later use.
The waiting list for surrogate eggs is between four and eight years. Only 900 out of the 4,000 required each year are currently donated. Details of all donors have been registered with the Human Fertilisation and Embryology Authority since 1991, and anyone over the age of 18 can already contact the authority to ask whether they were an IVF child. The government has to decide exactly how much other information can be given, before a 2009 deadline.
A total of 29,000 babies have been born in Britain using IVF, since the first successful procedure in 1978.