High-frequency continuum observations of young stars

31-GHz and/or 90-GHz radio continuum observations have been made towards 48 young stars. Only three signals are definitely detected and are shown to represent late O or early B stars. None of the 'continuum T Tauri stars' were detected, suggesting that these are unlikely to be hot stars. Some early B stars should have been detectable if they have normal Stromgren zones. Their undetectability may well signify that circumstellar dust modifies the ionization of surrounding gas.