Three biological parents for babies?

The U.K.’s assisted-reproduction watchdog, the Human Fertilisation and Embryology Authority, is asking the British public to weigh in on a new technique that would use DNA from a third “parent” to help eliminate serious diseases.

Currently illegal under British law governing fertility treatments, the practice could help avoid inherited diseases such as muscular dystrophy that are passed on to offspring only by mothers.

About in one in 200 children is born annually with such conditions, called mitochondrial diseases because they’re transmitted through the DNA in the mitochondria of the mother’s cells. Mitochondria are tiny structures that run cellular functions.

Most genetic characteristics (99.8%) are contained in the DNA of the cell’s nucleus–DNA that is inherited equally from both mother and father. A tiny amount of mitochondrial DNA is inherited from the mother only.

Known as mitochondrial replacement, the new technique could enable an affected woman to avoid passing a mitochondrial disease on to her children by using a donor’s mitochondria to engineer a genetically healthy embryo. A child born of this technique would therefore share DNA with three parents, albeit a tiny amount from the third-party donor. But the donor’s DNA would be passed along to future generations.

Mitochondrial replacement could potentially prevent a range of muscular, neurological, cardiac and gastrointestinal disease.

“The decision about whether mitochondria replacement should be made available to treat patients is not only an issue of great importance to families affected by these terrible diseases, but is also one of enormous public interest,” wrote Prof. Lisa Jardine, HFEA chair, on the organization’s website. “We find ourselves in uncharted territory, balancing the desire to help families have healthy children with the possible impact on the children themselves and wider society.”

As with all reproductive techniques involving donors, ethicists are concerned about the impact on the offspring’s sense of identity on finding out they are the product of donated genetic material.