Access Veto Systems
Type of reunion registry system. The veto is a document filed by one party to the adoption which registers that person's refusal to be contacted or denial of release of identifying information. In an access veto or nondisclosure request system, an adopted adult may receive identifying information about another party if no veto is on file. Some States may have provisions for a contact veto, permitting a party seeking information access to identifying information, including an original birth certificate, but prohibiting contact between the parties.
Source: Children Welfare Information Gateway