Hi Egnix,
Gel memory foam is regular memory foam with some gel added into it in various ways (see post #2 here) and memory foam is certainly not a natural material. Some versions of memory foam or polyfoam replace a small percentage of one of the two main chemicals used to make the memory foam or polyfoam (the polyol) with a plant oil based derivative but the majority of the material is still memory foam that is made with petrochemicals. The gel that is added to gel memory foam is a “safe” material (see post #4 here).
While all foam materials (including latex) will have some offgassing or VOC’s, the gel memory foam is made in North America which means the foam manufacturer would be CertiPur certified for harmful substances and VOC’s so there is some assurance that the VOC’s are below the threshold that most people would be sensitive to and by most people’s standards it would certainly be “safe enough”.
Phoenix