In some cultures, marriage is recommended or considered to be compulsory before pursuing any sexual activity.
When defined broadly, marriage is considered a cultural universal.
The definition of marriage varies not only between cultures or religions, but also within them throughout their histories, evolving to both expand or contract in what is encompassed, but typically it is principally an institution in which interpersonal relationships, usually sexual, are acknowledged or sanctioned.Individual means something that cannot be divided: a unit complete in itself.In the above quotations it refers to single human beings, which is what we usually mean when we say "an individual".Often, you have to change your opinions on related issues in order to honor that principle, or you have to throw out the principle and change your mind about the original question. You can't appeal to the Bible; in the Bible, God commands marriages between first cousins.Instead, advocates of laws against cousin marriage appeal to science. The group is people who are married to their cousins.