Pan-Species Gametes, also called PSGs, were bioengineered reproductive cells. They allowed Thayolen and their hybrid descendants to interbreed with individuals of almost any number of humanoid species. Each PSG contained nano-droids which would manipulate multiple species' gametes to be merged with the PSGs. The nano-droids then manipulated the DNA of the fetus, which resulted in selected features from both the standard gamete and the PSG. Fetuses created by PSGs always had high midi-chlorian counts.