DNA paternity testing can prove paternity to within 99.99% accuracy, more than acceptable as legal proof of fatherhood. What happens, however, if the suspected father is not available to provide a sample, or refuses to do so?
There is no better method of proving that someone is the biological father of his child than DNA testing. The DNA of the father and child can be compared to within 99.99% certainty, more than enough for courts legally to pronounce the biological father of a child - or even to legally deny it.
Many men are reluctant to take part in such tests for their own reasons, and some may be deceased or even unable to be contacted for one reason or another. In such cases there are ways of collecting samples and having the DNA test carried out.
Testing Blood Relatives to Prove Paternity
A child's paternity can be proved through a technique known as DNA relationship testing, which involves testing relatives of the alleged father. For this to be relevant there must be a proven relationship from the person tested to the father.
Grandparents, uncles, aunts, and even cousins, nieces and nephews of the child can be used as subjects. The match might not be perfect but there is only so far that such test can go, although for any but legal reasons, such matches are more or less conclusive.
What is conclusive is a DNA match for a male child using the Y chromosome. The chromosomes of a human being can be one of two sex types, known as X and Y. Human DNA consists 46 chromosomes, two of which determine the sex. During reproduction, the human egg contains 23 chromosomes, half of what is needed to form an embryo. One of these 23 is the sex chromosome, and in the case of the female egg this is a Y chromosome.
The sperm contains either an X or a Y chromosome, and when the sperm and egg combine to form the full complement of 46, the two sex chromosomes are either X-X (female) or X-Y (male).
A relatively new DNA analytical procedure is able to test repeating sections of the Y chromosome to prove paternity down the male line. Known as the Y-Short Term Repeats test (Y-STR), this can be used on blood male relatives, such as the child's grandfather on the male side, brother, cousins, nephews or uncles, all on the male side.
Because the Y chromosome does not change down the generations, it can be used to prove paternity or otherwise, even though the actual father is not available for testing. This form of DNA paternity testing might be required by the courts, in which case it would be organized by your attorney, but you can also contact the company that will be doing the test, and ask their advice on what is necessary and who should provide the sample.