'Three-Parent Babies' Could Be Born in Two Years

It sounds like some sort of dystopian dream, but if a team of scientists from the UK’s Human Fertilisation and Embryology Authority (HFEA) have their way—and it looks like they might—genetically modified “three-parent” embryos could be an available option in just a few years.

“Three-parent babies” isn’t a term the HFEA uses (it opts rather for “mitochondrial replacement”), and it’s not quite what it sounds; person number three doesn’t really get much of a look-in. They’d only contribute 0.1 percent of the kid’s DNA, and it wouldn’t be nuclear DNA—so it wouldn’t affect physical attributes like eye colour, or characteristics like intelligence, or whatever.

Mitochondrial replacement is essentially a proposed add-on to conventional in-vitro fertilisation (IVF). It’s targeted to women who are at risk of passing on mitochondrial disease to their kids if they have them naturally.

Mitochondria are present in a huge range of cells, and in simple terms they’re responsible for providing energy to the cell, converting energy from food into cell-powering ATP. But if there’s something wrong with a woman’s mitochondria, like faults in its DNA, that can cause genetic mitochondrial diseases that can be passed down to her children. The HFEA explains that one in 200 children are affected, and while some have no symptoms, others can suffer from a range of potentially severe conditions.

So the proposed solution: replace the woman’s defective mitochondria with someone else’s healthy mitochondria, i.e. a third person donor contributing to the baby mix alongside mum and dad. Sounds simple, right? And actually, the methods kind of are in theory. You take the nuclear DNA out of the woman’s egg and stick it in the cytoplasm of someone else’s egg that’s had its nuclear DNA removed but still contains the mitochondria. Then you add sperm and, voilà, it’s the birds and the bees as usual. Another option is similar, but swaps both parents' nuclear DNA into a new egg after its been fertilised.

In its newly published report, the third to consider the safety of the technique, the HFEA panel wrote that, “At each review, the panel has reached a view that the evidence it has seen does not suggest that these techniques are unsafe.” It recommends a few more experiments before the technique is offered clinically, but essentially gave it a stamp of approval. Reuters reported that the scientists told a briefing the treatment could be available in two years.

The sticky part, of course, is the ethics, and new laws would be required to make the procedure legal in the UK. It would be the first time that modified embryos would be allowed to make a kid, which has some worrying about the potential path to designer babies and the concept of "playing God". Those concerns, however, aren’t exactly new; they’re raised with any development in reproductive tech (and as someone born through IVF, I can only refute this kind of “slippery slope” argument. There's a line to draw, but allowing women to have healthy babies isn't comparable to selecting "designer" traits).

The ball’s now in the government’s park, and they’re considering the regulation necessary to green-light the procedure, which would make the UK the first country to allow it.