Final answer:
Relatives who have children together are at a higher risk for genetic disorders because of the increased likelihood of both parents being carriers for the same recessive genetic traits. Tay-Sachs disease, and others are autosomal recessive disorders that can be inherited if both parents contribute a recessive allele.
Step-by-step explanation:
Relatives who have children together have a much higher risk of having a child affected by genetic disorders. This is because when two individuals who are closely related produce offspring, they have a greater chance of being carriers for the same recessive alleles, which can lead to the expression of a genetic disorder if the child inherits the recessive trait from both parents.
Some diseases and disorders are caused by genes, and these genetic disorders can be passed down from parents to their children. For instance, conditions like cystic fibrosis, Tay-Sachs disease, sickle-cell anemia, and phenylketonuria are examples of autosomal recessive genetic illnesses where two carriers have a 25 percent probability of having a child affected by the disorder if they both pass on the recessive allele. A healthy person in a family where some members suffer from a recessive genetic disorder may want to know if they carry the disease-causing gene and what risk exists of passing it on to their children.
Conditions such as Down syndrome, hemochromatosis, hemophilia, and Huntington's disease are also genetic in nature and can be passed on to offspring. However, the inheritance pattern may vary, and in some cases, such as Down syndrome, age and other lifestyle factors can impact the risk level.