Randy does list Snowflake Frozen Embryo adoption in the resources section of his book ProLife Answers to ProChoice Arguments. The Snowflake site has some wonderful stories about couples who have adopted and carried these children to term. When it comes to adoption, Randy believes it is honoring to God and consistent with the prolife message. (Read an interview with Randy about adoption for more on this subject.)
However, the greater issue with the embryos is the fact that so many are created for IVF, not used, and then frozen. In an article on our site about the moral implications of fertility issues, Dr. Farnsworth explains what happens to the embryos that are not donated to other couples:
The frozen embryos have an uncertain fate. Some of them remain frozen for an inestimable period of time, children that have been created and then frozen! Does it seem right to create life and then leave it? Some of the frozen embryos may be thawed later for a repeat cycle of IVF, and most do not survive. In some cases embryos are donated to other couples or some may be donated for research (i.e.: killing them in the name of scientific study).
You can read more of Randy’s thoughts on frozen embryos in the article, “Are Frozen Embryos Persons Worthy of Protection?”