DNA technology revolutionized criminal law, family law and trust and estates practice. It is now revolutionizing immigration law. Currently the Department of Homeland Security does not require DNA tests, but it recommends these tests when primary documentation, such as marriage licenses, birth certificates and adoption papers are not available to prove the relationship between the U.S. citizen petitioner and the beneficiary who is seeking permanent resident status in the United States. DNA tests are attractive to the government as a result of administrative convenience and as a means of countering fraud, but adoption of a wholesale policy of DNA testing poses a host of potential problems. In an area of law where family reunification is described as the primary goal, an increase in the use of DNA sometimes results in separating families and other unintended consequences. By promoting the use of DNA evidence, the social interests that are paramount in a family relationship could become subservient to genetic interests. The beneficiaries could become mere genetic entities, whose biological relationship through their genes is paramount. This promotes the view that shared genes are the principal means of identifying human relationships and that one should be entitled to legal benefits solely on this basis. Quality control in the collection, storage and testing of samples, access of individuals to testing facilities, especially in developing countries, privacy interests and the potential for misuse of the results of these tests, particularly in preventing the admission of aliens on health grounds are among the potential problems identified in this article. Using examples from disciplines where DNA evidence has been adopted—criminal, family and estates and trusts law—this article will present a workable policy for the use of this technology in immigration law.