A lawsuit being heard this week in Pennsylvania could rewrite how the Defense of Marriage Act (DOMA) is applied across civil society, and potentially spark a dramatic expansion of the law’s terms that would force private companies to not recognize same sex spouses.

The lawsuit boils down to benefits due to the spouse of Sarah Ellyn Farley, who died shortly after a legal same sex marriage to her wife, Jennifer Tobits, in Canada. Because the woman’s parents refused to acknowledge their daughter’s relationship with her wife, they claimed that DOMA requires death benefits accrued by their daughter at the Cozen O’Connor law firm be paid to them, instead of her spouse.