Question

a set of twins are born. one exhibits signs of an inherited genetic disorder and the other
which of the following statements is true about the twins?
a. the healthy twin could still develop the same genetic disorder later in life.
b. either twin could pass the gene for the genetic disorder to their offspring.
c. both twins have the same dna.
d. the healthy twin is immune to all genetic disorders.

Explanation:

• Option A: For inherited genetic disorders, if one twin has it at birth, the healthy twin (if they don't carry the causal genetic variant) won't develop it later; this is incorrect.
• Option B: If the twins are fraternal (dizygotic), they share ~50% of genes. If the disorder is heritable, the affected twin carries the gene, and the healthy twin might also be a carrier (able to pass it to offspring). Even for identical twins, if the disorder is due to a de novo mutation in one twin, the affected twin can pass the gene, and if the healthy twin has the variant but no symptoms (reduced penetrance), they can also pass it. This holds true for relevant twin scenarios.
• Option C: Only identical (monozygotic) twins have identical DNA; fraternal twins do not, and the scenario doesn't specify twin type, so this is not universally true.
• Option D: No twin is immune to all genetic disorders; this is false.

Answer:

B. Either twin could pass the gene for the genetic disorder to their offspring.