Last month my former coauthor, Dr. William Cutrer, spoke in Washington D.C. at a conference on “Emerging Issues in Embryo Donation and Adoption.” After reading up on the literature, he wrote this to me:

“Embryo freezing [cryopreservation] involves gradually replacing the water inside each cell with a chemical related to antifreeze used in automobiles, so the water doesn't freeze, explode, and kill the cells and the baby. Tiny ice shards can penetrate/perforate the cell walls, killing the embryo in either the freezing or thawing process. If they freeze an eight- to sixteen-cell embryo, they expect a couple of the cells to be destroyed in the thaw, even in the embryos that survive—a testimony to the remarkable recuperative ability of the human embryo. But, knowing this makes me even more opposed to cryopreservation. We'd never risk a "real" baby that way, and I believe they are real babies.

I still favor the adoption of currently frozen embryos, but I'm even more opposed to cryo... freeze eggs, and gasoline prices, not babies.