Preservation techniques for human semen.

Sperm banking with the relatively simple and economical biologic freezer (Linde BF-5; Union Carbide Corporation, Linde Division, New York, N.Y.) was compared with controlled-rate freezer (Linde CRF-1; Union Carbide), using different freezing rates and cryoprotective media. The results were assessed by comparing prefreeze and post-thaw sperm motility. Our results demonstrate a significant loss of sperm motility with both techniques; however (1) complex cryoprotective medium (CPM) containing egg yolk produced better results than did 10% glycerol, (2) the rate of freezing at 10 degrees C versus 1 degrees C/minute did not produce a significant difference, and (3) results with the controlled-rate freezer and BF-5 were similar. We therefore conclude that sperm banking can be accomplished in a relatively simple and reliable way by using the BF-5 and CPM.