These eggs are removed and mixed with a man's sperm, and the resulting embryos can be stored and transferred back into the womb after cancer treatment is concluded. While that sounds straightforward it is not. Chemotherapy can cause premature menopause and it may be dangerous for women to take the hormones necessary for child bearing after her cancer treatment has concluded. Hormone treatments can increase the risk of recurrence for certain cancers. Finally, even in otherwise healthy women IVF and embryo reimplantation is by no means a sure thing.
Men have more options.
According to the authors, led by Dr. Ralph Brinster of the University of Pennsylvania School of Veterinary Medicine, the technique may someday be used to restore fertility to human males after cancer treatment. Brinster and his colleagues collected immature sperm cells, known as germ stem cells, from infertile mice, then transplanted them into the testes of a different strain of infertile mice. Eighty percent of the recipient mice began to produce normal sperm, the researchers found. And four out of nine male mice that mated with normal female mice were successful in reproducing. An accompanying article by two Scottish researchers, Drs.