A baby boy was conceived using a controversial technique that mixes DNA from three people. The US-based team carried out the procedure in Mexico which brought up a lot of ethical concerns; Mexico has less clear oversight of human embryo modification than the United States. The mother had faulty mitochondria, so they transferred the nucleus of the mother’s egg cell to the egg of a donor with healthy mitochondria and removed that nucleus to put in the other nucleus- this technique is known as spindle nuclear transfer. The egg with healthy mitochondria and the mother’s nucleus was then fertilized with the father’s sperm; five embryos were modified, but only one was implanted into the mother and she gave birth. This technique allowed the baby to inherit nuclear DNA from both parents and mitochondrial DNA from the donor. This is the first baby to be conceived using the spindle-transfer version of mitochondrial-replacement therapy. It is amazing how far science has come and how much it can help people who thought that they could not have kids before can now conceive them. I think that the ethical concerns should be ironed out before other procedures take place, but it is great that individuals that were not able to conveive prior to this are now able to.