Before DNA test how was paternity tested?

Prior to the advent of DNA testing, paternity testing was conducted using a variety of methods, including:

Blood Group Analysis: Blood type inheritance patterns can be used to determine if a man is likely to be the father of a child. This method is based on the fact that certain blood group alleles are dominant and others are recessive. By analyzing the blood types of the mother, child, and alleged father, it is possible to determine if the alleged father could have passed on the child's blood type. However, blood group analysis alone is not always conclusive as there can be multiple potential fathers with compatible blood types.

Human Leukocyte Antigen (HLA): HLAs are proteins found on the surface of cells that play a role in the immune system. HLA inheritance is similar to blood group inheritance, with certain alleles being dominant and others recessive. HLA testing can be used to determine if a man is likely to be the father of a child by comparing the HLA profiles of the mother, child, and alleged father. Similar to blood group analysis, HLA testing is not always conclusive on its own.

Anthropological Assessment: In some cases, physical traits, such as facial features, body proportions, and hair color, may be used in paternity assessments. This method relies on the assumption that children inherit physical traits from both their mother and father. However, anthropological assessments are highly subjective and can be unreliable due to variations within families and the influence of environmental factors.

Exclusionary Testing: In cases where an alleged father is known not to be the father of a child, exclusionary testing can be used. This involves analyzing specific genetic markers, such as enzymes or proteins, that are known to be inherited from the father. If the alleged father does not possess the genetic markers that the child has inherited, it can be definitively determined that he is not the father.