Paternity testing is done to prove whether a man is the biological father of a child. It is mostly done for legal matters such as adoption or child custody rights. If the man is biologically related to the child the test will return a result greater than 99.9% if they are not biologically related the test will return a 0% result.
How do Paternity Tests work?
Paternity tests are done by collecting samples of DNA from both the man and the child or individual in question. This can be a blood sample or a mouth swab. The DNA is compared to see if the two individuals share biological markers. When a baby is conceived the 23 chromosomes present in the woman’s egg and the 23 chromosomes present in the man’s sperm combine to give a total of 46 chromosomes to the child. These 46 chromosomes are presents in every cell of the body. This means that a DNA paternity test will show the same 23 chromosomes in the father and the child. To do this scientists separate out the DNA using splicing techniques. This DNA is then bound to nylon membranes and developed on a film. This gives a distinct black and white pattern. The two patterns are compared for similarities. This process is repeated a number of times using different parts of the DNA. If enough similarities are found then the paternity test is considered to be 99% accurate. If less than two matches are made then the test has determined that there is a 0% chance of the man being the father.
Paternity testing can be done at any time including prior to birth and after death. To collect the child’s DNA prior to birth a CVS or Amniocentesis needs to be performed to collect appropriate cells for testing. There are risks to both the fetus and the mother involved in both these tests so they need to be considered carefully.