I am engaged to a man and we are getting married in aug. we had a baby together in April he's on and everything. And all of a sudden my ex boyfriend writes his mom to tell me he wants a dna test on my daughter when he gets out of prison do I have any rights to refuse it when he decides to try to get a dna test done?

You may refuse it, up and till the time that he goes to court and serves you with a court order for a test.

Is it possible, if so, did you do one with the current boyfriend to make sure it was his.

You will not be able to refuse a court ordered paternity test. Unfortunately you can not just choose a new father for your child, as DNA is what establishes paternity. The father has rights as well.

What was your ex in jail for?

You can file for child support and full custody once the paternity test establishes the child's father.

As already said you can refuse up until a judge orders the test be done. At that point you must submit to the test or sit in jail yourself. If your soon to be husband is proven to be the father then life will go on with out a hitch... if the ex is proven to be the father then you will get a support order and you will have to file for custody with him having visitation.

I guess I will add, I will assume you could "refuse" the judges order, he would either
1. have you locked up in jail till you agree
2. fine you a cetain amount of money a day till you agree
3. have you locked up and allow the jail hospital to take the sample anyway.