Disease model pigs produced by nuclear transplantation, disease model pigs exhibiting stable phenotypes and production methods thereof are provided. Chimeric pigs for producing disease model pigs exhibiting stable phenotypes, genital glands thereof, and germ cells thereof are also provided. A method for producing a genetically modified disease model pig, includes: (a) transplanting a nucleus of a genetically modified cell into cytoplasm of an egg; (b) developing an obtained clonal embryo in a womb of a female pig to obtain an offspring; and mating the obtained offspring or having the offspring undergo sexual reproduction to further obtain the genetically modified offspring as a disease model pig.