Y chromosome plays key role in medical and forensic application especially paternal inheritance. Beyond the sex determination, several Y chromosome linked genetic disorders can be diagnosed. 5% of the Y chromosome comprises of pseudoautosomal regions (PAR1 and PAR2) on the Yp arm and Yq arm respectively. Remaining 95% of the Y chromosome does not recombine during meiosis. The non-recombining region of the Y chromosome is designated as "NRY" (non-recombining region). NRY region includes the SRY gene or Male Specific Y (MSY) chromosome. In view of the fact that the Y chromosome is traversed to next generation, it is frequently used in genealogy to track the male ancestry. Both medical and forensic aspects of Y chromosome have been reviewed systematically according to the advancements of technology in the molecular genetics field.