Effect of freezing on the relative escape force of sperm as measured by a laser optical trap

To determine the possible effect of freezing on sperm escape force as measured by laser trap. Controlled clinical study. Normal volunteers, academic setting. Normal, healthy volunteers. Sperm selection, freezing and thawing. Measurement of relative (sperm) escape force before and after freezing. Comparison of escape force as a measurement of freezing effects. Wide individual variations noted, with some individuals showing significant increases or decreases. The relative escape force in fresh (76.1 ± 31.1 mW) and in frozen-thawed samples (75.6 ± 40.0 mW) were similar. Freezing does not affect the relative escape force of normal sperm. Any possible detrimental effect of freezing on sperm may be related to other sperm functions.