Cryopreservation of human spermatozoa. IV. The effects of cooling rate and warming rate on the maintenance of motility, plasma membrane integrity, and mitochondrial function**Supported by grants from the National Institutes of Health, Bethesda, Maryland (R01-HD25949 and K04-HD00980); Parke-Davis; Methodist Hospital; and by the Office of Health and Environmental Research, United States Department of Energy, Washington, D.C., under contract DE-AC05-840R21400 with Martin Marietta Energy Systems.††Presented in part at the Annual Meeting of the American Society of Andrology, New Orleans, Louisiana, April 13 to 16, 1989, and at the Annual Meeting of the American Society of Andrology, Tampa, Florida, April 17 to 19, 1993.‡‡The submitted manuscript has been authored by a contractor of the United States Government under contract DE-AC05-840R21400. Accordingly, the United States Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes.