Article from Grace Ruga Regarding Outcrosses in a Breeding Program
CFA allowed domestic outcross breeding to the American Curl until January 1, 2015, TICA still allows using outcrosses in breeding programs. Developing the breed from domestic outcrosses (specifically non-pedigreed cats) is why the American Curl has known genetic defects. Other "man made" breeds that were created by combining two or more pedigreed cats will incorporate the genetic defects and health issues from each of those breeds into the offspring. The large gene pools provided by the domestic outcrosses does not do that.