Your best protection is to buy from a sperm bank since sperm bank donors have no way of knowing if they have any kids, let alone who the mothers are. However, one of the many disputed issues in this newly developing area of the law is whether the identity of the donor should be secret or whether states should enact legislation permitting disclosure to the child of his/her biological father. If you opt out and go private, your best first step is to see a lawyer to draw up an artificial insemination contract. However, states are divided on whether the contract is enforceable. Some states won`t enforce these contracts as a matter of public policy (parents should be on the hook for child support and should get visitation). Some enforce the contract (consenting adults can decide these things for themselves). And the law is constantly changing. Termination of parental rights is probably the best bet if you insist on going private. Check with a lawyer to see if a private party can bring this suit and if it can be brought before the birth of the child (in California, for example, your rights can be finalized through a pre­birth Judgment of Maternity and Paternity).