The answer depends on whether the state in which the employee resides recognizes same-sex marriage.
Supreme Court ruling. On June 26, 2013, the U.S. Supreme Court issued a ruling striking down Section 3 of the Defense of Marriage Act (DOMA), which had previously provided that the definition of marriage applied only to the legal union of one man and one woman, and that the definition of spouse referred only to a person of the opposite sex who was a husband or a wife. In response to the ruling, the Department of Labor (DOL) updated its Fact Sheet #28F to define a spouse as “a husband or wife as defined or recognized under state law for purposes of marriage in the state where the employee resides, including ‘common law’ marriage and same-sex marriage.”
Impact on FMLA. The revised fact sheet clarifies that FMLA leave is available to same-sex spouses who reside in a state where same-sex marriage is legally recognized. Thus, lawfully married same-sex couples who live in a state that recognizes same-sex marriage are entitled to up to 12 weeks of FMLA leave in a 12-month period to care for a seriously ill spouse or for activities that arise in connection with a military spouses’ deployment, and up to 26 weeks of caregiver leave for a military spouse who is seriously injured or ill, if they are otherwise eligible for FMLA leave.
Employers are not required to make FMLA leave available to same-sex spouses who reside in a state that does not recognize same-sex marriage.
Source: DOL Fact Sheet #28F, Qualifying Reasons for Leave under the Family and Medical Leave Act, revised August 2013, http://www.dol.gov/whd/regs/compliance/whdfs28f.pdf.