Identical twins have the exactly the same DNA, and developed from the same original fertilised egg. So DNA testing cannot tell which of a pair of identical twins is the father. (Or for that matter the mother, but usually we know for sure which woman gave birth to a child!)

There are also non-identical twins. Their DNA is no more similar than any pair of siblings. DNA testing could establish which of a pair of non-identical twin brothers was most likely the father of a child, but with a lower degree of confidence in the result than if the potential fathers were unrelated.

There are cases where this has actually happened:

http://abcnews.go.com/TheLaw/LegalCenter/story?id=3195632

In general DNA tests the closer the relationship of the potential fathers, the more work would have to be done, and the less reliable the result. Even if two cousins were the potential fathers, there would be increased risk of error, as cousins share 12.5% of their DNA. A man's uncle or nephew shares 25% of their DNA, while a father, son or brother shares 50%.

http://www.horizonscounselling.com/frequently_asked_questions1.html

http://www.paternitytests.info/index.php/dna-paternity-testing-articles/dna-paternity-testing-of-related-potential-fathers/

http://www.cellmark.co.uk/dna_testing/twin_dna_testing.php

Asker's Rating:

Permalink | Report