We report the first observation of the 108Xe → 104Te → 100Sn α -decay chain. The α emitters, 108Xe [Eα=4.4 (2 ) MeV , T1 /2=5 8-23+106 μ s ] and 104Te [Eα=4.9 (2 ) MeV , T1 /2<18 ns ], decaying into doubly magic 100Sn were produced using a fusion-evaporation reaction 54Fe (58Ni, 4 n ) 108Xe, and identified with a recoil mass separator and an implantation-decay correlation technique. This is the first time α radioactivity has been observed to a heavy self-conjugate nucleus. A previous benchmark for study of this fundamental decay mode has been the decay of 212Po into doubly magic 208Pb. Enhanced proton-neutron interactions in the N =Z parent nuclei may result in superallowed α decays with reduced α -decay widths significantly greater than that for 212Po. From the decay chain, we deduce that the α -reduced width for 108Xe or 104Te is more than a factor of 5 larger than that for 212Po.