The most relevant constitutional provisions are the equal protection and due process provisions of the Fourteenth Amendment. You can find the text of the Fourteenth Amendment in any version of the United States Code, official or annotated, online or electronic.
You can retrieve federal or state code sections easily if you have the citation of them from a secondary source or from a case. You can always search the code databases to find the sections, but there is a genetics-specific legislative database that you should know of:
One way to obtain cases on a topic is to find relevant journal articles or books which usually cite leading cases. From there, you can Keycite (on Westlaw) or Shepardize (on Lexis) the cases to find other relevant cases and journal articles. ETHXweb which indexes leading bioethics cases is another good resource.