Some fallacies in the computation of paternity probabilities

Area of Science:

• Forensic genetics
• Legal medicine
• Probability theory

Background:

• Legal identification of fathers using "paternity probability" is common in European and American courts.
• Existing literature lacks fundamental criticism of the logical basis for these probabilistic computations.

Purpose of the Study:

• To critically evaluate the logical basis of "paternity probability" calculations.
• To identify and explain the fallacies inherent in current paternity probability computations.

Main Methods:

• Logical analysis of the "paternity probability" formula and its underlying assumptions.
• Examination of the interpretation of the computed "paternity probability" figure.
• Assessment of the evidentiary basis for genotype assumptions in post-inclusionary computations.

Main Results:

• The "paternity probability" figure is not the actual probability of paternity.
• The denominator in the likelihood ratio is based on unsupported and potentially contradictory assumptions.
• Post-inclusionary computations rely on speculative genotype data, lacking scientific evidence.

Conclusions:

• "Paternity probability" calculations suffer from fundamental logical fallacies.
• Current methods for computing paternity probability are not scientifically sound.
• It is recommended to suspend the use of "paternity probabilities" as positive evidence until these issues are resolved.