The frequency of consanguineous matings due to multiple use of donors in artificial insemination.

The amount of inadvertent inbreeding as a result of donor anonymity in artificial insemination has been estimated. A child from a first-cousin mating or closer is expected approximately once every 41/2 years in the United States as a result of artificial insemination by donor. Since a child with unknown paternity seems less likely to mate with paternal relatives than is a child with known paternity, artificial insemination by donor may actually reduce the average inbreeding of the population. Nevertheless, to reduce recessive diseases, inbreeding should be kept to a minimum by limiting the number of children produced by a single donor. Formulas are presented for local risks of inbreeding based on the number of children per donor.