If fraternal (or dizygotic) twins are more likely to be concordant for a trait than other siblings, can it be concluded that the higher concordance rate is due to the greater degree of genetic relatedness?
a. Yes.
b. Yes, but only if the siblings studied are of the same sex and age.
c. No, because the greater similarity can be attributed to environmental influence.
d. No, because fraternal twins are no more genetically alike than other siblings.
