Same-sex marriage, also known as gay marriage, is marriage between people of the same sex, either as a secular civil ceremony or in a religious setting. 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.
DNA between siblings are similar if you share the same biological parents. The genetic information you gain comes from both of your parents, and are a result of fertilization of 2 haploid cells fusing to form a zygote that has a diploid number of chromosomes.
Sibling DNA testing http://www.dnatesting.com/dna-paternity-test/more-dna-testing/sibling-dna-test determines if two individuals share one or both parents. DNA Testing with a possible brother or sister can help answer paternity questions when the possible father is not available to be tested. Half siblings share one parent. For example, a brother and a sister may share the same mother, but not the same father.