Less than three months ago, I was quoted in the New York Times about the possibility of having fractional biological parents. Research in non-human primates showed how it was possible to create a child with genetic material from one father and two mothers. While splitting up "legal" parenthood into many parts is nothing new, having more than two genetic parents (what I call "fractional parents") is.
And now, it appears, researchers have created a human embryo with three genetic parents (chromosomal DNA from one father, chromosomal DNA from one mother, and mitochondrial DNA from a different mother). Assuming the embryo could be brought to term, the approach could enable women with damaged mitochondrial DNA to still become (fractional) biological parents. To be sure, the third parent's mitochondrial DNA would have just a tiny role in the child's total genetic profile. But biological parenthood could become even more diffuse in the future. Such developments raise interesting moral and legal questions about the nature of parenthood that I discuss here.