(Comic I made three years ago. Ignore the twitter logo)
34 points
Serious answer: eggs have a protective barrier around them, so sperm actually need to group in bunches to break the barrier, and a single lone sperm is incredibly unlikely to do well on its own. As such the ones that have a higher chance of success are actually the ones that are last and get in after the barrier’s been weakened.
15 points
There’s also evidence that eggs ‘choose’ the sperm, or at least filter out some sperm based on genetic factors.
15 points
8 points
8 points
