To piggyback on what Don wrote, the Gibson Co. Health Dept. website (http://www.gibsoncountyhealth.com/index.php/vital-health-rec...) states that its records start at 1882. Depending upon your needs, alternate records that may sometimes be used to "prove" a birth include a baptismal record, Bible entry, a death certificate (which often gives the date or year of birth and sometimes the parents' names), census records (especially 1900), pension applications, and published obituaries. The death certificates I received several years ago from the Gibson Co. Health Dept. for ancestors born before 1882 included the individuals' ages at death.