Posted 7/7/2020 10:09 AM (GMT -6)
Yes it's the salazopyrin (sulfasalazine) that's responsible. I have not read anything about steroids causing that issue.
"For men with IBD, sulfasalazine can decrease sperm counts and sperm motility, causing a functional azoospermia; the other aminosalicylates do not have this effect. The sperm effects are reversible by discontinuing the sulfasalazine. "
If this concerns you, ask about switching to another mesalamine/aminosalicylate/5-ASA like asacol, pentasa, lialda/mezavant which do not have that effect.