The IRS, in Notice 2014-19 and related FAQs, says that retirement plans have to recognize same-gender spouses and spells out how. The notice and FAQs, which the IRS issued April 4, are a follow-up on Revenue Ruling (Rev. Rul.) 2013-17, which provided general guidance on the tax implications of the Supreme Court’s decision in U.S. V. Windsor (the DOMA case). Notice 2014-19 and the FAQs specifically focus on retirement plans.