There have been more than 3,000 births in the UK from the use of a technique called Intra-Cytplasmic Sperm Injection (ICSI). This technique, used when the male partner has a low sperm count, involves a single sperm being injected directly into an egg.
The Human Fertilisation and Embryology Authority (HFEA), the body that governs all fertility clinics in the UK, has approved the establishment of the register by Dr Alastair Sutcliffe, senior lecturer at the Royal Free and University College Medical School in London, and Dr Mike Hawkins, from the Department of Public Health and Epidemiology at the University of Birmingham.
"We will need at least 5,000 children born by ICSI to compare with 5,000 `control' children to establish whether the ICSI children are at a higher risk of having major congenital abnormalities," Dr Hawkins said yesterday.
ICSI, which was first used in Britain in 1993, is now used in one-quarter of all in vitro fertilisation (IVF) treatments. Its initial success rate of 4 per cent has risen to 21.6 per cent.
Some fertility experts have argued that ICSI is a genetic time bomb because the treatment "bypasses the selective barriers of evolution".
Indeed, research has suggested that children born by ICSI have more genetic defects. In one study, ICSI children showed twice the incidence of birth defects than children conceived naturally.
The only British research conducted, however, has shown that at approximately 18 months of age there were no major developmental differences between children born by ICSI and those conceived naturally.
Dr Sutcliffe, who presented the final report of his findings at the British Fertility Society annual conference this week, said: "Our findings are reassuring for parents of ICSI children. We did find a trend for them to have more minor congenital disorders but it was not significant," he said.
The 429 toddlers who took part in the study were tested on their eye- hand movements and mental and social development. Follow-up tests are planned when the children reach the age of five. "At 18 months it is difficult to pick up subtle differences in development," Dr Sutcliffe said. "A national register would enable us to determine the true extent of any differences."
All fertility clinics in the UK have been invited to participate in the establishment of the register. Parents of ICSI children will be asked to fill in questionnaires on their children's birth weight, any birth defects and their social class. Their anonymity would be guaranteed. Eventually, blood tests and physical examination of the ICSI children may also be conducted as part of the study.
"The study would probably take five years to complete," Dr Hawkins said.
"We would also want to look at differences between single and multiple births."