Loote: You should ask your father or read Mahabharat yourself to find out how Dhritrastra got 100 sons! Although, I do not remember in detail, one thing I can tell you is that they were not born "each year" .. that would take over 100 years for all. They were all born by what modern medicine may say as "Artificial insemination" or "Test Tube babies". All 100 were born almost in the same time, Duryodhan being the first!