Proving paternity when the father is deceased is often necessary even when the father supported the child while alive. Government agencies may require actual proof of parentage before the surviving parent or child can access public benefits. Or you may need to prove paternity in order to access shares of the father's estate that have been designated to heirs. Laws vary by state for establishing paternity, but they generally require proof by similar means.
Produce a birth certificate that lists the deceased man as the father.
Provide documentation that the alleged father and child share a surname. Many states will acknowledge shared surname as evidence of parentage.
Provide documentation that the alleged father claimed the child as a dependent on taxes.
Obtain a sample of the alleged father's DNA (genetic material). Eye colour, blood type, and other physical characteristics may identify the possibility or plausibility that a man is the biological father, but these factors cannot alone establish paternity. Obtain a sample of the alleged father's DNA from a tissue sample taken during medical treatment or testing while the alleged father was still alive.
Obtain a DNA sample of the alleged father's closest relatives, if you have exhausted all the options for obtaining his own DNA. DNA from the alleged father's mother and father or from other children belonging to him can establish paternity to a high degree of probability. Courts and government agencies will typically acknowledge paternity established in this way.
Obtain a DNA sample of the child whose parentage is in dispute.
Locate a laboratory or medical facility that specialises in blood and tissue testing for the purpose of establishing paternity. Typically, you will only have to wait two weeks for results.