Stock and flow diagrams. Submodel of the supply of medical specialists 2008-2025. The number of doctors of each sex in each one of the 47 specialties depends on the new arrivals to the market (inmigration, training) and on the exits (retirements, drop-outs, mortality). In each step of the simulation the model shifts the medical population one year ahead, with 36 age-sex intervals (30 to 65 years of age). Age-sex pyramids for each specialty and year in the time horizon 2008-2025 are calculated.