History of DNA Testing
DNA paternity testing is accepted throughout the world as an undisputed method of confirming biological paternity. Initially it was not recognised in many countries but as DNA testing was discovered, the role of the test became a vital tool in court cases. Paternity testing was developed in 1925 and it was thought the introduction of this test goes some way in explaining why fertility dropped in the 1930s.
Paternity and Blood Types
Historically, before the 1920s in most American states a jury would decide whether or not child support should be provided in a child welfare dispute as there were no scientific methods to determine who the biological father was. It was up to the jury to believe either the mother’s story or the alleged father’s story. But by 1935, paternity testing was used as evidence in some states. It’s thought in those areas fertility decreased. The first test used blood types as an indicator of family relations.
Blood Paternity Testing Unreliable
But blood testing isn’t conclusive. If for example, a mother with Type A blood had a baby with Type A, the father could be of any blood group. It’s thought the ABO blood testing to determine paternity only helped around 15% of cases. Developments in identifying blood types helped make testing more accurate but the margin for error was still high. In England however, this test was not used routinely in the courts in the 1920s and 1930s, as common law meant a jury decided child support cases. Research shows that countries that used paternity testing in the legal system in the 1920’s and 1930’s saw a bigger drop in fertility then those that didn’t.
But it was the discovery of reliable paternity DNA testing that really changed how child support cases were handled. The undisputed accuracy of testing meant there was a much higher incentive for men to avoid or take more care to prevent unwanted pregnancy. In other words, the higher the accuracy of paternity testing, the more incentive there is for men to use contraception.