“Designer babies” could be less than two years away, a doctor has said.
Controversial gene editing allows scientists to remove DNA that codes for diseases from an embryo before it is implanted into a woman.
Critics argue we should not be “playing God”, with the practice potentially allowing parents to one day select for other desirable traits, like blue eyes, height or even musical talent.
With gene editing being a new technology, some worry the consequences are unknown, with studies suggesting it could even increase the risk of cancer.
But Dr Kevin Smith, from Abertay University in Dundee, claims it is now sufficiently safe to be introduced in the next one-to-two years.
“Human [DNA] is by no means perfect, with evolution having furnished us with rather minimal protection from diseases that tend to strike in our later years, including cardiovascular disease, cancer and dementia,” Dr Smith said.
“Genetic-modifying techniques offer the prospect of protecting future people against these and other common disorders.
“If several common disorders could be avoided or delayed by genetically modifying humans, the average disease-free lifespan could be substantially extended.”
Writing in the journal Bioethics, he acknowledges gene editing has “residual safety concerns” and “negative publicity”.
Dr Smith therefore recommends “delaying” designer babies for a “modest period of time, in the order for one-to-two years”.
This comes after a Chinese scientist claimed to have genetically-modified twins to be HIV resistant last year.
The unverified claim broke Chinese law, with critics accusing him of acting “in pursuit of fame and fortune”.
“If such negative attitudes to biomedical innovation had prevailed in the 1970s, the development and use of IVF - a massively beneficial medical technology - would have been severely delayed, and indeed might never have come to fruition,” Dr Smith said.
Why are designer babies controversial?
Known as CRISPR, gene-editing technology allows doctors to cut, replace or tweak a specific strand of DNA.
Supporters argue genetically-modifying embryos could keep people healthy into old age, with genes that code for diseases like Alzheimer’s being discarded.
However, critics worry it may lead to parents selecting for traits that have nothing to do with health.
And with the new technology likely being extremely expensive, only well-off people could afford it, leaving the poor unfairly burdened with diseases.
In countries like the US where people pay for health insurance, companies may refuse to cover those who have not had their genes edited.
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Parents may also not get the outcomes they were hoping for, with the DNA of an embryo undergoing some modification in the womb.
And it’s not just our DNA that shapes us; upbringing and life experiences have a significant impact on traits like intelligence.
“Your child may not turn out to be the three-sport All-American at Stanford,” Dr Richard Scott Jr, a founding partner of Reproductive Medicine Associates of New Jersey, said.
Studies even suggest gene editing could cause cancer, rather than eradicating the disease.
US scientists found the practice can cause cells to multiple abnormally and become malignant in the laboratory.
“Gene editing is experimental and associated with off-target mutations, capable of causing genetic problems early and later in life, including the development of cancer,” Professor Julian Savulescu, from the University of Oxford, told the BBC.
Are designer babies legal?
Designer babies are illegal in the UK.
In 2016, the UK Human Fertilisation and Embryology Authority (HFEA) allowed a certain group of scientists to genetically modify embryos for research purposes.
The team, from the Francis Crick Institute in London, “turned off” genes that prevent IVF success and cause miscarriages.
They only analysed the embryos' early development, with the cells not being allowed to grow into babies.
Since then, UK scientists can carry out experiments on discarded IVF embryos as long they are destroyed immediately afterwards.
Gene editing is not illegal in the US as such, however, research cannot be paid for with federal funds.
In 2015, the US National Institutes of Health said it “will not fund any use of gene-editing technologies in human embryos”.