A new study by scientists at Temple University in Philadelphia has shown that the DNA of babies conceived through IVF differs from that of other kids, putting them at higher risk of diseases such as diabetes and obesity later in life.
According to researchers, their study could explain why IVF babies tend to be at higher risk of low birth weight, defects and rare metabolic disorders.
The changes are not in the genes themselves but in the mechanism that switches them on and off, the study of which is known as epigenetics.
"These epigenetic differences have the potential to affect embyronic development and foetal growth, as well as influencing long-term patterns of gene expression associated with increased risk of many human diseases," Times Online quoted Professor Carmen Sapienza, a geneticist at Temple University in Philadelphia, who jointly led the research, as saying.
There is a possibility that such changes could be transmitted to the children of IVF babies, meaning they could spread through the human gene pool.
For the study, Sapienza and his colleagues took blood samples from the placenta and umbilical cords of 10 IVF children and 13 children who were naturally conceived.
They studied the DNA of cells taken from the blood to see if there were differences in the level of methylation.
This is the process by which molecules known as methyl groups are attached to genes to shut them down when they are not needed.
The results showed that the level of methylation in the cells taken from IVF babies was significantly lower - implying that some genes were becoming active at the wrong times.
"We have shown that in vitro conception is associated with differences in gene methylation and that some of these differences may affect gene expression," said Sapienza.
According to the researchers, the findings could have serious implications for the booming industry in assisted reproduction.
The study has been published in the Human Molecular Genetics journal.