Legally, a child’s father is the mother’s husband or a man who has been
assigned paternity in a court proceeding. Biologic paternity is virtually
irrelevant without legal recognition. Courts may choose to transfer legal
paternity from one man to another, but they endeavor not to disturb paternity
when it will render an otherwise legitimate child a bastard. Physicians should
also avoid casting doubts on paternity when a family is already in crisis.
Although physicians should not lie to patients, there is enough uncertainty
about paternity determinations to allow room for differing interpretations. Even
tissue typing can be confused by mutation, the presence of related males
among the candidates, or laboratory error.
It is best to avoid questions of paternity unless they are directly relevant to the
patient’s medical condition or care. If the father is concerned about possible
genetic disease in his child, the information gathering should be directed to the
disease, not the paternity. Physicians should decline to test a child to
determine paternity unless it is a medical necessity. (This is usually an issue
only for certain rare genetic diseases and as a side issue in tissue typing for
organ transplantation.) If a court orders paternity testing, the physician must
honor the order. But the physician acting as an expert witness in such a case
should inform the court of the limitations of the tests and avoid making any
unequivocal pronouncements of paternity.
While modern DNA testing techniques make paternity testing much more
certain, they do little for the social consequences flowing from such tests. DNA
testing is now available and marketed directly to the public. If the reasons for
testing are social, not medical, physicians should advise patients to seek this
information outside the medical setting. If the issue is legal paternity or child
support, the state child welfare agency should be involved.