Almost seems like a stupid question, but I guess many people are rather ignorant of their first amendment rights. Of course we have a right to blaspheme any topic, religious or otherwise. But, always a but, we also have a responsibility and should be accountable to our actions. If you are not willing to put your real name on your comments, maybe you shouldn't be saying it in the first case. Further, if you say something actionable, libelous, etc., then you should be prepared to be accountable for your actions. Aside from that, in my opinion, blaspheme away.
There are statutes that forbid the use of “Fighting Words.”
Ask Publius.