by Martin Hutchinson
BBC News Online health staff in Madrid
A major study of babies born after common fertility techniques has confirmed that they are just has healthy as children conceived naturally.
IVF produces healthy babies
IVF itself, and ICSI, in which a single sperm is injected into the egg to fertilise it, have now been in use for 25 years and 11 years respectively, and there are substantial numbers of children conceived using both methods.
However, some doubts are still being expressed, particularly about ICSI children, fuelled by fears that the process of selecting just one sperm and using a needle to place it inside the egg may have a negative effect on the development of babies born this way.
The latest study, presented at the European Society of Human Reproduction and Embryology annual meeting in Madrid on Wednesday, compared the progress of hundreds of IVF and ICSI babies from five EU countries with their normally-conceived peers.
The researchers say it lays to rest fears that there are any major health problems associated with being a test-tube baby.
IVF and ICSI children had similar birth weight, and height aged five, to non-IVF children, the study found.
They had no significant differences in medical illnesses, or in verbal performance and total IQ - although girls scored higher than boys in all three groups studied.
In addition, IVF and ICSI children were no more likely to have behaviour problems, and their parents no more likely to have higher levels of stress.
Overall, the results are reassuring and lay to rest fears that have been expressed about the health and welfare of children conceived through IVF and ICSI
Professor Christina Bergh,Sahlgrenska University Hospital
There was only one difference - ICSI children had a higher rate of malformations.
Other studies have reported these increases in malformations, mainly genital and mostly minor, and experts believe that because men who are candidates for ICSI are often subfertile, they may be carrying genes that predispose both to this, and increase the chance of genital defects.
In normal circumstances, they would never be able to pass these on by having children.
Professor Christina Bergh, from Sahlgrenska University Hospital in Goteborg, Sweden, one of the investigators, said: "This is the most comprehensive study ever done on IVF and ICSI children.
"Overall, the results are reassuring and lay to rest fears that have been expressed about the health and welfare of children conceived through IVF and ICSI."
A separate study presented at the conference took a closer look at the genetic safety of ICSI.
Researchers from Cornell Institute for Reproductive Medicine in the US screened both fathers and their ICSI babies to look for abnormalities.
They concluded that any abnormalities in the children had been passed down from their fathers, and were not new genetic faults introduced by the ICSI process itself.