positional objectivity

In 1995 Karen Keegan, mother of three, was told that she needed an immediate kidney transplant. (RadioLab, 2008) In the search for a suitable donor, her husband and her two sons underwent DNA testing. The results were her two sons' DNA did not match hers. From a medical point of view this meant that she was not their mother. She insisted that the test be repeated since they were "obviously" wrong. She had given birth to her babies and had experienced the pain of delivery. However, the new tests confirmed the previous results. Clearly there had been no laboratory mistake. This was quite a puzzling situation, for although a mismatch between a father's DNA and a child's DNA is not unheard of, there had never been a case where a mother's DNA did not match her children's. Doctors initially thought that there was some sort of a mix up, such as switching of babies at the hospital, but then dismissed this possibility because the father's DNA matched his sons'. Since for medical doctors "DNA is never wrong" they suspected that Karen was hiding something. Some of the doctors even went as far as to suggest that she had implanted her womb with another woman's baby and lied about it. After investigating hospital records and so forth, the doctors decided to test some other tissues in her body, such as her thyroid, bladder and skin. The results of these tests were perplexing for they identified two sets of DNA, and two sets of DNA meant the existence of two different people. In other words, the tests indicated that there was another person inside Karen. Furthermore, this other person was the mother of her two boys. Eventually, the doctors concluded that Karen is a twin.1