Most people afflicted with recessive disorder with recessive disorders are born to parents who are not affected at all by the disease. Most genetic disorders of humans are caused by recessive alleles. Dominant alleles on the hand cause lethal disorders, however they are less common compared to the recessive alleles disorders, this is because most individuals carrying a lethal dominant allele have the disorder and they die before pass it to the offspring, while the individuals with the recessive lethal genes are more likely to be healthy and reproduce.