I present recent radiation hydrodynamical simulations that demonstrate that X-rays from young stars may play an important but previously unsuspected role - i.e that of evaporating gas from their circumstellar discs. Since these discs provide the birthplace of planets, a process that erodes these discs has important implications for planet formation. We demonstrate that this scenario is compatible with a range of diagnostics such as the distribution of infrared colours of T Tauri stars as revealed by Spitzer, together with blue-shifted emission lines in NeII and OI in these systems. We show that the model provides a natural explanation for the observed anti-correlation between X-ray luminosity and the possession of a disc in young stars. Finally we highlight how disc studies at low metallicity may be used to determine whether photoevaporation or planet formation is the major mechanism for disc dispersal.