# What statistical test should I use (biostatistics)

I am comparing sperm motility between 2 sets of samples (2 groups). Motility just means weather the sperm are alive or not, in this test I am just looking at that. If its moving, then its alive (I have the motility values as percentages, for example an ejaculate from 1 person might have 20% motile sperm and 80 immotile). It is important to mention that sperm motility decreases with time after ejaculation. I have 2 different groups of people. The control group has had sperm motility (percentage of moving sperm cells in ejaculate) measured in various time periods (1–8 hours after ejaculation). The second group is the treatment group. Here, an extender liquid has been added to the ejaculate which should prolong the motility time (the sperm should stay alive for longer). The sperm motility of this group has been measured later than the control group$$`$$s (6–24 hours after ejaculation). I want to test weather the extender liquid has a significant effect on motility over time. How should I approach this?