Is creatine bad for male fertility?

There are no studies. Although there are anecdotal reports supporting both sides of the controversy; to date, there have not been any scientific studies documenting safety or nonsafety. Therefore, if you are trying to conceive, probably wiser to stay away from it.
No, just stop there! Protein and Amino Acids supplements are fine for male fertility, but anabolics including dhea and androstendione will suppress sperm production. Stay natural!