Scientists have been studying sheep ovaries as they are similar to humans. They took whole sheep ovaries, froze them and then thawed them. As results, they got successfully produced embryos.
Even though fragments of ovarian tissue have been frozen and transplanted before, the scientist wanted to experiment with the whole ovaries as this would enable preservation of vital blood vessels which would otherwise have to re-grow.
Ovaries from eight sheep were removed and frozen. After some time they thawed and re-implanted the ovaries back into the animals and got five successful transplantations. Eggs obtained from two of these sheep subsequently produced six embryos.
The scientists are hoping that they will be able to do the same thing with human eggs in the near future in order to help women who are facing infertility.