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.
The answer to this question is usually that siblings share 50% of their DNA. But this is misleading. Depending on how you count rearrangements, deletions and neutral codon assignment changes, all human genomes are between 99.0 and 99.9% identical [1] .