Based (i) on data for the Pb 2 Sr 2 YCu 3 O 8 (PSYCO) homologues with Y replaced by R = Ce or R = Am, and (ii) on experimental facts for Nd 2-z Ce z CuO 4, we conclude that all the main high-temperature cuprate superconductors are p-type, and that very likely none are n-type.