There is such a method and a certain basis. It is a coagulation phenomenon in which prothrombin and coagulin are specifically combined in blood. However, this method does not have the ability of absolute judgment. In other words, there is not necessarily a parent-child relationship, and there is not necessarily a blood relationship. The blood drop identification of brother-sister relationship is also not rigorous. Specific identification should be based on DNA testing. By comparing the allele loci of parents and siblings.
Source of information: Chinese website of Gene Biotechnology Application Co., Ltd.
References:
www.genegle.com