“Double-donor” IVF involves creating embryos from an egg donor and a sperm donor. Pregnancy success rates are typically based on the age of the woman’s eggs. So, egg donation cycles can often result in a much greater 50% live birth rate provided all other fertility factors are optimal.
Embryo adoption cycles offer the transfer of fertilized eggs, usually from couples who have donated their embryos. In contrast to egg donation cycles, embryo adoption cycles may be less successful because the age of the eggs (and sperm) are not always ideal to maximize outcomes.