Epic’s MetaHuman Avatar tool now has the abilty to import scans of real people, this is open for developers currently, but watch this space as I will predict it will not be long before you are able to create your own metahuman that looks like your twin.
To caveat this was found via Roadtovr.com and they quoted this
“There’s still some limitations, however. For one, hair, skin textures, and other details are not automatically generated; at this point the Mesh to MetaHuman feature is primarily focused on matching the overall topology of the head and segmenting it for realistic animations. Developers will still need to supply skin textures and do some additional work to match hair, facial hair, and eyes to the person they want to emulate.
The MetaHuman tool is still in early access and intended for developers of Unreal Engine.”