Technically, it's possible that the progenitor sperm cells could all get compromised and not sure what your sperm will be like if they get infected with mRNA. If it ruins the tail / movement or what, rendering it useless / infertile.

But this is all speculation, if there is true longitudinal data tracking, we will know within a couple months if there is a fertility impact with more data points.

Albeit right now, we we have is going to be anecdotal, enough anecdotal will give a retrospective view on it as well which might be more apparently before the prospective data downstream is available.