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.
Sibling DNA Testing. Sibling Testing is a DNA test process that is performed to determine if two people share one or both parents. For example to determine if they are full or half siblings. This is an indirect method to prove family relationships when the alleged father is not able to perform a paternity test.