HeredityGeneticsHistory, 19th CenturySoftwareElephantiasisDiseases in TwinsTwins, MonozygoticTwins, DizygoticSwedenEnvironmentGenes, RecessiveGenetic Predisposition to DiseaseRisk FactorsFamily HealthPhenotypePedigreeGenes, DominantGenetic LinkageSex FactorsAge FactorsBiological EvolutionGenetic VariationPolymorphism, Single NucleotidePrevalenceGenotypeQuestionnaires