If twins marry twins, their children would be related more closely than typical cousins; genetically, they would be similar to half-siblings.
Understanding the Genetics
Here's a breakdown of what happens when identical twins marry identical twins:
- Identical Twins: Identical twins share nearly 100% of their DNA. This means that genetically, they are essentially the same person.
- Marrying Twins: When two sets of identical twins marry, it's like siblings from one family marrying siblings from another family.
- Children's Relationship: The children of these couples would be cousins, but because their parents are genetically identical, the children would share about 50% of their DNA, the same amount shared between half-siblings.
Visualizing the Relationship
| Relationship | Percentage of Shared DNA (approximate) |
|---|---|
| Full Siblings | 50% |
| Half-Siblings | 25% |
| Typical First Cousins | 12.5% |
| Children of Twins Married to Twins | 25% (Similar to Half-Siblings) |
Key Considerations
- Appearance: The children of these unions may exhibit striking similarities due to the increased genetic overlap.
- Legal and Social Implications: Legally, they are cousins. Socially, their unique genetic relationship might be a topic of interest.
- Quaternary Twins: Although not technically "twins," the children from such unions can be described as quaternary twins because of their unusually close genetic relationship. This is mentioned in the reference where Dr. John Pappas states that they share DNA in the same way siblings do.
Summary
The children of identical twins who marry each other are genetically related as closely as half-siblings. They're legally cousins but share a much higher percentage of DNA than typical cousins.
