The idea of "three-parent" babies isn't new but the big step to turn research into reality didn't happen until recently. On Thursday, the U.K.'s fertility regulator, the Human Fertilization and Embryo Authority, granted doctors the license to create babies through an IVF technique that uses the DNA of two women and one man. The UK can expect its first "three-parent" baby to be born as early as December 2017.
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Wait, hold up. What is a "three-parent" baby?
"Three-parent" babies are born through a groundbreaking mitochondrial pronuclear transfer technique. They would have DNA from a mother, father and a bit from a female donor. To put it simply, doctors replace an egg's defective mitochondrial DNA from the mom with healthy DNA from a female donor. The egg is then fertilized with the father's sperm.
But some researchers take issue with the name "three-parent" baby, arguing that mitochondrial DNA doesn't contribute to a person's traits and the donor shouldn't qualify as a "parent."
Why is this necessary?
The procedure is designed to prevent inherited genetic diseases. Think of the mitochondria as each cell's energy-generating battery. If there's something wrong with the battery, it could cause incurable, debilitating conditions like heart problems, muscular dystrophy or severe neurological disorders. By replacing defective mitochondrial DNA, the hope is that mothers wouldn't pass on defective mitochondrial mutations to their kids.
About one in every 4,000 children are born with mitochondrial diseases every year.
"Patients will now be able to apply individually to the HFEA to undergo mitochondrial donation treatment at (Newcastle Fertility at Life), which will be life-changing for them, as they seek to avoid passing on serious genetic diseases to future generations," announced Sally Cheshire, the fertility regulator's chair.
Fertility specialists are calling Thursday's approval a milestone for science and the medical community.
"It's a great testament to the regulatory system here in the UK that research innovation can be applied in treatment to help families affected by these devastating diseases," said Mary Herbert, professor of reproductive biology at Newcastle University.
How controversial is this?
Critics argue the technique blurs the line between what's ethical and unethical, and say it's a dangerous step that will lead to "designer babies."
"It is at the very least reckless and irresponsible given that we have absolutely no idea what the long-term consequences are to us interfering with the human genome," said Mark Bhagwandin, a pro-life spokesman for the charity Life. "Whilst we are deeply sympathetic to the plight of people with mitochondrial-related diseases, the end does not always justify the means. Our understandable search for therapies to help overcome illness and disabilities must be done in an ethical way and balanced against the unconditional acceptance of all human beings, whatever differences they may have."
Is this the first three-parent baby?
No, the U.K. became the first country in the world to specifically make mitochondrial replacement legal in 2015 but the first mitochondrial transfer baby was born in April 2016 after U.S. doctors performed the procedure on a Jordanian couple in Mexico.
In Ukraine, "three-parent" baby methods aren't used for preventing diseases but as fertility treatments, which many researchers see as an ethical problem. With IVF success rates much better now than two decades ago, they argue there is less justification for experimental techniques.