Once again, this is more complicated than the question seems. First let us understand what marriage is. Marriage is a practice common to all cultures in all ages. It is, therefore, a natural institution, something common to all mankind. At its most basic level, marriage is a union between a man and a woman for the purpose of procreation and mutual support, or love. Each spouse in a marriage gives up some rights over his or her life in exchange for rights over the life of the other spouse.
Now to the question submitted: The "straight answer" is simply "yes," but let’s understand also the "why."