Which type of twins share a disease more frequently?

• A. Fraternal twins
• B. Identical twins
• C. Half-identical twins
• D. Control twins

Answer: (B)

Identical twins, also known as monozygotic twins, share a higher frequency of certain diseases compared to fraternal twins and other types of twins. This is primarily because they originate from a single fertilized egg that splits into two embryos, resulting in twins that have nearly identical genetic makeup.

Since identical twins share virtually the same genetic material, any hereditary or genetic predisposition to diseases is more likely to manifest similarly in both individuals. This contrasts with fraternal twins, or dizygotic twins, who develop from two separate eggs fertilized by different sperm, leading to different genetic combinations. Thus, they do not share the same likelihood of developing genetic conditions to the same extent as identical twins.

Half-identical twins, or sesquizygotic twins, are also less common and share some genetic material but not as much as identical twins. Control twins do not refer to a specific category in genetic studies related to disease sharing. Therefore, the higher concordance of diseases among identical twins emphasizes the significance of genetic factors in disease susceptibility.