Ten babies, including one set of twins, have been born to women whose IVF treatment included a controversial embryo screening procedure which has only recently been allowed in Britain.

The technique, already deplored by some campaigners who say it is unethical, will offer hope to women in their late 30s and 40s who might otherwise not be able to conceive, and may change general IVF practice.

The Assisted Gynaecology and Reproduction Centre in London, responsible for all the successful births, said yesterday that the babies born since February 22 were doing well.

The first was a boy born to a woman who had returned to Kuwait after her treatment.

The clinic said another 30 women were pregnant by the technique which is already used in Italy, France and the US. In all, 110 women had undergone screening before implantation of embryos.

Mohamed Taranissi, the director of the clinic, only revealed the extent of the use of the screening yesterday. Considerable publicity was given to the CARE IVF clinic at the Park hospital, Nottingham, in June when it announced that a 42-year-old woman who had also undergone the procedure was pregnant.

It was widely reported as the first pregnancy in Britain to result from aneuploidy screening. These checks ensure that embryos with too few or too many copies of certain chromosomes are not used.

In fact, women who had undergone treatment at Mr Taranissi's clinic had already given birth. He did not blame the CARE clinic for the misunderstanding. "They are not supposed to know what is going on in other units." But he has raised the matter with the regulators, the human fertilisation and embryo authority (HFEA), which, he believes, should not have allowed the impression to persist.

The technique should improve the prospects of pregnancy for increasing numbers of women nearing middle-age who want to raise a family. It is licensed by the HFEA, which regulates clinics, only for women over 35 or for those who have suffered repeated miscarriages, a history of failed IVF treatment or those who have a family history of babies with chromosomal abnormalities.

Mr Taranissi said he believed the technique would become an "integral part" of all IVF treatments in future. It would mean clinics could use fewer embryos, minimise the chances of multiple pregnancies and use embryos that had the best potential for implantation.

He said: "Older women who are at increased risk of producing a child with Down's syndrome , or with other age-related chromosomal abnormalities, can now use aneuploidy screening rather than waiting for prenatal diagnosis which may lead to termination of the pregnancy, often at an advanced stage."

A 42-year-old patient who had previously suffered a miscarriage due to severe foetal abnormalities, recently gave birth to a boy. She said: "We desperately wanted to try for a baby, but we could not face the prospect of waiting three months to find out if the pregnancy was normal. Fortunately, using aneuploidy screening , the clinic was able to identify the one normal embryo we had and gave us peace of mind."