What would most likely cause two parents without any symptoms of a genetic disorder to have children who express the condition? pick one

1 Epigenetic modification causes the children to express dominant alleles for the condition

2 Both parents pass on a recessive allele on to the children

3 Codominant alleles cause the children to express the disease and healthy alleles

4 The parents must have had some symptoms but were not recognized due to being significantly less severe than in the children