I am over the age of 18, married and have a child on the way. My parents live in Ohio, where I used to live but I've recently moved to Virginia because my husband's in the military.
Disowning a family member is usually relevant in two situations: 1) where a person who is of emancipal age (16 in Virginia) desires to be freed of parental control and (2) where a person wants to block a blood-kin family member from inheriting in the event that that person dies without a valid Will. But there is no legal action for an adult child to 'disown' one's parents, due to the overall needs of the State to be sure that destitute adults are not solely the financial burden of the state in the future.
You are over age 18 and in Virginia and the rest of the U.S., that is the end of inquiry #1. They have no legal right to contact you, but you'll have to do the heavy lifting of notifying them in writing that you want no contact with them.
You have the legal right to notify your parents that you want no further contact with them of any kind, up to and including a Notice of No Trespass. That has to be served upon them by a sheriff's deputy or Police officer, depending on the service rules in whatever county they reside.
LEGALLY, however, if your parents ever need your financial assistance, the state has the right to come after you for contributions to their support.
If they are harassing you by telephone, or engaging or attempting to engage in identity theft of yours, then you need to contact the police department in which they reside AFTER you have issued and had them served with the Notice of no Trespass, to file criminal charges.
Make sure, if you are dealing with attempted identity theft, to talk to your bank and supply notice to the three big credit reporting agencies (Equifax, Experian, and TransUnion) AFTER you have had a successful legal proceeding against them once they've violated the No-Trespass notice.
My strongest recommendation is to ask for a Peace Bond, rather than a criminal charge of Trespass, because that way they have a financial incentive to stay away.
However, unless your parents are seriously sociopathic, it would be better if you could try family therapy to heal the issues, as there are very few relationships which cannot be fixed with the right effort.
Legal issues often depend on the specific facts in any given case or situation. Please do NOT utilize the information you receive as either a binding legal opinion in your case, nor presume that I am your counsel because I've answered a question you had. Any legal representation is accomplished by written contract ONLY, signed by each of us.
Many people have different understandings of what 'disown' means.
Your parents already have very limited rights to your child (if you say they can't see the child, then they can't), you likely aren't claiming them as dependents on hour federal income taxes, you are in the age of majority, and your parents have no legal hold over you, you are not require to name them in your will--in fact you may explicitly state in your will that your parents cannot take from your estate and you can list other individuals as guardians, ahead of your parents.
In a sense, there is no 'ownership' to break-you are (or you can be) as free from them as you desire.
Assuming you want to ensure your child has little or no contact with your parents, you might consider contacting a probate/trust/wills attorney in your local area spend some time discussion your reasons, options, etc.
The attorney will be able to help you take the proper course of action to ensure your relationship with your parents is exactly what you want it to be.
You can use Avvo.com to find an attorney, or contact your local bar association and ask for a referral or contact Military Legal Service Office that supports your husband’s command and speak with a JAG who can guide you just as well.