According to George and Roberta Poincar, extinct multicellular life, like dinosaurs, cannot be brought back to life for two major reasons: DNA extracted from insect inclusions in Amber are damaged, and certain key components are missing. There are DNA repair systems, but until what is missing and what actually needs to be repaired is known, nothing can be done. Secondly, even if complete DNA from and extinct animal was obtained, it would have to be inserted into a host egg, and be convinced that it is in an embryonic state, and the egg would have to be made to develop normally without it turning into a mass of undifferentiated tissue.

The oldest ever DNA extracted from an insect inclusion in Amber is 125 million year old early Cretaceous Lebanese Amber, (on July 19th, 1992).