The title is at least confusing, but FTA:<p>> <i>According to IVF Japan, which announced the cases in Osaka, mitochondria were extracted from egg precursor cells in the patients' ovaries by way of laparoscopic surgery and other means, and were injected into the women's eggs alongside sperm at the time of in-vitro fertilization.</i><p>Anyway, it's not very clear in the article that they have a control group. A control group is important to be sure that the improvement in the pregnancy rates are due to the treatment and not due to other factors.<p>I guess they choose a group of women that had problems to get pregnant. But how many of them would have got pregnant with the usual in vitro fertilization? Did they select a group that have good health or is quite young?<p>Perhaps some small details changed from the previous attempts of these women. Just to make up a few, perhaps this time they get more rest, or a better diet control, or more vitamins/iron/folic acid/whatever.<p>All these things are very difficult to measure and the only way to remove the bias is a control group.