The most significant threat to the usefulness of twin studies is the fact that the majority of monozygotic twins
A) do not share the same amniotic sac during prenatal development.
B) do not develop from the same zygote.
C) develop from two separate eggs that are fertilized by two separate sperms.
D) always share 100 percent of the same DNA.

Question

Quizplus · Accepted Answer

Monozygotic twins sharing the same amniotic sac is not a significant threat to the usefulness of twin studies. The significant threat is the assumption that environmental factors are the same for both twins, which might not always be the case. However, the options provided do not directly address this issue. Among the given options, A is the closest to a potential threat because sharing the same amniotic sac (or not) could imply different prenatal environments for the twins, which could affect the assumption of equal environmental conditions for both twins in studies. However, this explanation is provided with the understanding that the question and options might not fully capture the complexities involved in the threats to the usefulness of twin studies.

The Most Significant Threat to the Usefulness of Twin Studies