Synthesizing the DNA itself is not the only problem however.

You then have to get that DNA into a working living form state so that normal cell processes can continue:
* for <viri> see: <synthetic virus>
* for bacteria, you have to inject it into a cell
* for placental animals, you also have to somehow simulate a compatible placenta. It is likely easier for eggs.

Multicellular questions:
* https://biology.stackexchange.com/questions/8590/can-extinct-animals-be-cloned

Apparently achieved for the first time in 2021: https://www.jcvi.org/research/first-self-replicating-synthetic-bacterial-cell by the <J. Craig Venter Institute>.


Discussion on "Species bootstrapping from DNA" by Ciro Santilli 32