“…This, in turn, leads to an increase in swimming trajectories in all three dimensions and sperm velocity, resulting in a stronger swimming force, essential for penetration of the zona pellucida. 13 In the past couple of years, several studies used DHM to track sperm cell trajectories in three dimensions 7,34,51,55,[76][77][78][79] to analyze sperm head morphology 56,80,81 or flagellar movement of free-swimming 7,34,76,80 or tethered sperm. 7,82 Most of the used setups differ in the time resolution.…”