The feminism argument
There is a compelling feminist argument cascading off of marriage equality. By breaking down the hierarchies and gender-identified roles of traditional marriage, it frees women from the constraints of those pre-defined roles. Traditional marriage’s implied protectionism of women, and subordination of both women and children can no longer be socio-normative. Marriage can no longer become an avenue for subjugating women, instead providing them the opportunity to define their own social, legal, and economic goals on their own terms, even if those terms happen to fall into the realm of traditional arrangements. When there is no gender-specific identification of the marriage constituents, gender-based hierarchies evaporate, creating true gender equality.
Kim, Suzanne A. "Skeptical Marriage Equality." Harvard Journal Of Law & Gender