How Paternity Testing Is Done
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Testing
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Paternity testing is done to clear up any confusion over who a child's father is. In such cases, body specimens from the mother, child and suspected father are tested to see if DNA shows whether it's possible the man and woman could have genetically produced the child. Paternity testing can be performed either before the child's birth (pre-natal) or after, (post-natal). There are risks to pre-natal testing, including possibility of miscarriage or harm to the baby as a result of the invasive procedures.
Amniocentesis
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Paternity tests done before a child is born involve either amniocentesis or chorionic villus sampling (CVS). Amniocentesis is a procedure where amniotic fluid is removed from the sac which surrounds the baby in the womb. After ultrasound guidance to determine the baby's location, a long needle is inserted through the mother's abdomen and into the uterus where the amniotic sac rests. Samples are then extracted and DNA tested for compatibility with the suspected father's genes.
CVS
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CVS can be done abdominally or cervically to obtain testing samples of chorionic villi, the tiny tentacles found on the uterine wall which contain the same DNA as the fertilized egg. For the abdominal procedure, a needle is used to enter the mother's abdomen and, with ultrasound, it is guided to the placenta where a tissue sample is extracted. After scrubbing and cleansing of the genital area have occurred, a small tube is inserted into the cervix and, with ultrasound, guided through the vagina to the placenta where a tissue sample is removed. Samples are compared for compatibility with the male's DNA.
Post-natal
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After the birth of a child, paternity testing is done via a DNA test which compares samples from mother, child and suspected father. Tests can be performed on blood, umbilical cord, semen, hair, tissue or buccal (cheek) swab samples. Results will determine the genetic compatibility of the three subjects and the probability that the male fathered the child.
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