https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4463894/

This study showed some parameters of sperm quality appeared to be adversely affected, but that the affects appeared to recover after discontinuation of the SSRI.

I've a feeling that the studies so far made have not been extensive enough to draw firm conclusions from, but would tend to regard any overall risks as likely within the same realm of parallel risks encountered in the course of normal activity, given that the SSRIs have been in use for a long enough period for a generation of users to have engaged in parenthood.