The study looked at how sperm movement and changes in sperm structure relate to the success of fertilizing human eggs in a lab. They found that the way sperm move after being incubated for 6 hours can predict how well they can fertilize eggs. By analyzing specific characteristics of sperm, they were able to accurately predict which samples would have high or low fertilization rates. This suggests that assessing sperm movement and structure could help predict the success of fertilizing human eggs in vitro.