We took a paternity test and I'm the biological father. She got married a week after she had the baby and he signed the birth certificate. She let me visit with the baby twice (he's 5 months old) now they won't let me see him at all. I even gave her husband a copy of the paternity test results. They said if I try to see him they will file harassment charges against me. What rights do I have since his name is on the certificate?

You have no rights. He is the legal father therefore you quit asking them for visits and get a lawyer and go directly to court. Only a court ordered DNA test will hold up so you will have to do another one after the judge orders it. Then when the results come back the judge will issue an order for child support and a visitation order as well as the birth certificate to be changed. You really need to act now (since you didn't when you first found out).

Was the paternity test court ordered ? Did he sign the BC after you took the test ?