Scientists in Japan have transformed mouse skin cells into eggs and have managed to obtain fertile offspring after their fertilisation (See Nature article HERE). This study represents the first production of eggs completely in vitro.
In 2012, mouse skin cells were reprogrammed into stem cells similar to embryonic stem cells and then induced into primordial germ cells (PGC). However, in order to get the PGC to derive into mature eggs, they had to be transferred to the ovaries of live mice (see HERE). The following breakthrough took place in July 2016, when a team of investigators from Tokyo reported the transformation of PGC extracted from mouse foetuses into eggs, without using a live animal (http://www.pnas.org/content/113/32/9021). Now, the cycle has been completed: from skin cells to functional eggs completely in vitro.
These findings come after investigators in China announced in February that they had produced rudimentary mouse sperm (spermatids) in vitro. Although spermatids are not fully mature cells, the investigators managed to obtain offspring.
Ethical assessment of artifical human eggs
If the protocol works with human cells, eggs could be obtained from the skin of a woman and also from a man, which could then be fertilised. For this reason it has been speculated that in the future, there is a possibility that same sex couples could have children with the genetic material of both fathers.
Among the ethical problems raised by this possibility are those inherent to in vitro fertilisation, the enormous number of human embryos that would be destroyed in researching and putting this technique into practice, the need to use a surrogate, using the woman as a mere incubator and the fact that the child produced in this manner would not be genetically linked to any woman, i.e.