In-vitro fertilisation (IVF) could alter the human genome by allowing defective genes that would normally die with the carrier to be passed onto future generations, according to Dr Hans Hanevik, who leads the fertility department at Norway's Telemark Hospital.
Millions of babies born through IVF are likely to carry the genes that caused their parents’ fertility problems, meaning they might also need artificial help to conceive when they are eventually ready to have children.
As they reproduce, the defective genes will continue to spread, Dr Hanevik is expected to tell the European Society of Human Reproduction and Embryology (ESHRE) at a conference in June.
“In accordance with the principle of evolution, subsequent generations will thus be genetically adapted to an environment in which reproduction is increasingly dependent on technological intervention,” Dr Hanevik has written in an abstract for the conference in Vienna.
Around 300,000 babies have been born through IVF in the UK since 1991. This accounts for more than one in 40 of the 750,000 babies born annually in Britain, and a similar proportion in other western countries.
The number is high enough to have a measurable impact, the fertility specialist has said.
“IVF is not just a treatment for infertility, but also a technological intervention at the point in a human life cycle where natural selection operates at its strongest,” writes Dr Hanevik,
“Although it is a great medical achievement, it circumvents a range of reproductive barriers.”
However, other specialists have argued that many couples who struggled to conceive are not genetically compromised, but simply have “plumbing” problems.
“Women may have fallopian tubes blocked by appendicitis and men may have undescended testicles or have had a vasectomy. IVF can overcome these problems,” said Gill Lockwood, medical director of Midland Fertility Services, which was the UK’s first clinic to achieve live births from the mothers’ own eggs.
“Even if they do have gene problems is that a reason to stop them being parents? IVF can bring delight and joy to people who finally get a baby – and to the siblings, grandparents, aunts, uncles and so on,” she added.
Dr Hanevik stressed that he was not criticising IVF, but highlighting the need for more detailed discussion about its effects.
In a previous paper, he claimed the long-term implications of IVF have not been thoroughly analysed due to a reluctance to consider the effects from an evolutionary perspective.
“To point out that IVF may favour disease-prone individuals or lead to reduced fitness over generations could surely be provocative, but is worth considering,” he wrote.
In 2017 nearly 55,000 patients had 75,000 fertility treatments, with 93 per cent having basic IVF, according to data from the Human Fertilisation and Embryology Authority,
Around 22 per cent of these resulted in live births — a low success rate linked to the genetic defects that cause infertility.