Children conceived using donated sperm will not be given the right to discover the identity of their biological fathers, says the government.

Some feared any moves to remove anonymity would discourage future donors from coming forward.

The decision flies in the face of advice from the UK's fertility treatment regulator that names should be revealed.

Currently donors remain anonymous and the 1,100 children born every year in the UK as a result of insemination from sperm banks will grow up never knowing about their biological fathers.

A spokeswoman for the Department of Health said: "We can categorically say we are not going to remove anonymity for donors."

Those who favour change argue that children born as a result of donor insemination can be psychologically damaged by discovering in later life that they will never know their biological father.

As researchers discover more genetic factors in diseases, future generations are likely to need to know their true background.

A spokesman for the Human Fertilisation and Embryology Authority said that it would need to hear the Department of Health's formal decision before giving any reaction.

She said that the decision had been a difficult one for the government.

However, she added: "When the authority considered the question of donor anonymity it felt that it was important that donor anonymity should be ended.

"It felt that it was appropriate for people to have access to information about their genetic parents."

Birth certificates

Dr Mohammed Taranissi, from the Assisted Reproduction and Gynaecology Centre in London, told The Observer: "I think you are going to have great problems with donors coming forward unless their anonymity is preserved."

A BBC survey last year of 82 donors at three sperm banks found the majority would not continue to donate if they could not remain anonymous.

In Sweden, where the law has been changed and donors are known, many infertile couples travel to Denmark, where donors are still anonymous, for treatment.