In comparison to concordance rates for autism in dizygotic twins, monozygotic twins

are _______ likely to develop the same illness.
A. significantly less C. significantly more
B. somewhat less D. somewhat more

To determine the answer to this question, we need to understand what concordance rates refer to in the context of twin studies. Concordance rates indicate the percentage of twin pairs for whom both twins have the same condition or illness.

Monozygotic twins, also known as identical twins, share the same genetic material, as they originate from one fertilized egg that splits into two. On the other hand, dizygotic twins, also known as fraternal twins, develop from two separate eggs fertilized by two different sperm cells, resulting in genetically different siblings.

Given this information, we can now deduce the correct answer by considering the question's options:

A. Significantly less: This option suggests that monozygotic twins are less likely than dizygotic twins to develop the same illness. However, that is not the case in this scenario, so this answer is incorrect.

B. Somewhat less: This option implies that monozygotic twins are slightly less likely to develop the same illness compared to dizygotic twins. But this is also not accurate, leading us to eliminate this option.

C. Significantly more: This option implies that monozygotic twins are more likely than dizygotic twins to develop the same illness. This is the correct answer. Research has shown that autism has a higher concordance rate in monozygotic twins, indicating a stronger genetic component in its development.

D. Somewhat more: This option suggests that monozygotic twins are slightly more likely to develop the same illness compared to dizygotic twins. While this choice could be potentially plausible, it is not the most accurate option, and thus, it is incorrect.

To summarize, the correct answer is C. Monozygotic twins are significantly more likely to develop the same illness, including autism, in comparison to dizygotic twins.