Laws that treat married persons in a different manner than they treat single persons permeate nearly every field of social regulation in this country -- taxation, otrts, evidence, social welfare, inheritance, adoption, and on and on.
Chambers, David L. "Marriage Today: Legal Consequences for Same Sex and Opposite Sex Couples." Law Quad. Notes 40, no. 2 (1997): 60-70. (Adapted from an essay originally published as "What if? The Legal Consequences of Marriage and the Legal Needs of Lesbian and Gay Male Couples." Mich. L. Rev. 95, no. 2 (1996): 447-91)