Abstract: The turbulent generation of large scale magnetic fields is driven by the transport of magnetic helicity, which is robustly conserved in conducting fluids. Some simple scaling laws emerge from this. These can be extended by considering the relationship between shear and rotation in turbulent convection. This work can be directly applied to stellar magnetic fields for fully convective stars. Surprisingly, the same scaling laws seem to apply generally, even in the presence of stellar tachoclines. I will also discuss the prospects for applying these insights to laboratory experiments.