Same-sex unions are recorded in the history of a number of cultures, but marriage or similarly formalized same-sex unions were rare or nonexistent in other cultures.
Using this measure, siblings are actually 99.95% the same. The 50% refers more to the amount of DNA we get from mom and the amount we get from dad. So we are more similar to our relatives than we are to a mouse. Let's explore in a bit more detail what the 99.95% and the 50% numbers mean.
Accreditations apply to Legal DNA tests. A sibling test starts with the analysis of known relatives. Siblings do not share the same mother and they want to find out if they share the same biological father. Siblings share the same mother but are unsure if they share the same biological father.