Eggs created from stem cells in fertility breakthrough In the new study, the scientists transformed skin cells into personalised stem cells, which were then fertilised via IVF and ultimately resulted in three fertile baby mice. Safety concerns must be addressed, particularly into the long-term health of the resulting offspring, before researchers come any closer to determining whether the treatment could be viable in humans. The researchers wrote in the latest online issue of the journal Science: "Our system serves as a robust foundation to investigate and further reconstitute female germ line development in vitro (in the laboratory), not only in mice, but also in other mammals, including humans." Dr Allan Pacey, senior lecturer in reproduction and developmental medicine at the University of Sheffield, said: "What is remarkable about this work is the fact that, although the process is still quite inefficient, the offspring appeared healthy and were themselves fertile as adults. This is a great step forward, but I would urge caution as this is a laboratory study and we are still quite a long way from clinical trials taking place in humans.