The development of inducible pluripotent stem [iPS] cells is terribly exciting. Generally, veterinary science has been helpful, barring one anomaly that is that no one got intracytoplasmic sperm injection (ICSI) to work in animals. In horses ICSI is extremely difficult. ICSI did not work when they tried it in mice. It worked in humans by accident in Brussels and the humans were able to take advantage of it. Subzonal insertion of sperm (SUZI) was tried and the sperm was injected into the cytoplasm of the egg. However, all the other developments such as egg and embryo freezing, were started in mice and then moved to larger animals. If an embryonic stem cell line is developed from a female blastocyst, then we will only be able to generate X carrying sperm and not Y carrying sperm.

Embryo cryopreservation is crucial for both the efficiency and the safety of assisted reproduction treatments. The potential risks of damage for cryopreserved-thawed embryos include exposure to medium biochemical contaminants, ice crystal formation within the embryo, toxic effect of cryoprotectants, damage during thawing process, physical damage during embryo manipulation, and DNA damage during embryo storage; but freezing itself cannot be considered a mutagenic procedure. Conventional embryo freezing concerns multicell embryos. Cryopreservation of early-stage embryos can be considered a valid alternative to conventional embryo cryopreservation. Cryopreservation of unfertilized oocytes presents more technical problems than early-stage embryo cryopreservation. The most alarming risk related with oocyte cryopreservation is aneuploidy in embryos conceived with this method. Children born from cryopreserved oocytes should be accurately monitored to ascertain the correct growth and development and to exclude possible genetic anomalies and malformations.