The headline reads: Ban on scientists trying to create three-parent baby. Apparently, Chinese researchers created fetuses (one of which was aborted and the other two dying in the second trimester) with the genetic material of three people. Here is a fairly succinct description of what was done:
The process involves taking the nucleus - which contains all genetic material - out of an unhealthy egg and inserting it into the egg structure of a donor from which all genetic material has been wiped.
The resulting embryo contains all the genetic make-up of the infertile woman but also mitochondrial DNA from the donor egg. Mitochondrial DNA is in effect the powerhouse of all cells and is common to everyone, but it contains tiny and subtle differences in each individual. Therefore, human nuclear transfer creates an embryo with the genetic make-up of two mothers and a father.