Sperm sexing technology-the transition to commercial application. An introduction to the symposium "update on sexing mammalian sperm".

Over the past decade, procedures for sexing mammalian sperm by flow cytometry/cell sorting have been refined sufficiently for large-scale commercial application in cattle; millions of doses of sexed sperm are sold each year for artificial insemination. Furthermore, more than a hundred babies are born annually from use of sexed human sperm via artificial insemination or in vitro fertilization, and to a lesser extent by injection of single sperm into oocytes. Semen sexing technology is also being applied for various objectives in a number of other species. Accuracy of sexing is around 90% in most species. However, this technology is still rather expensive, and fertility of sexed sperm is lower than unsexed controls in most instances. Speakers in this symposium, "Update on sexing mammalian sperm," held in San Diego, California on 3 January 2009, presented the latest research on sexing sperm, including documentation of success rates. The written versions were peer-reviewed and follow in this issue of Theriogenology.