A civil union between a man and a woman is a state-created legal status that gives an opposite-sex couple most of the same rights and responsibilities as marriage within that state, but no recognition from the federal government. Only a handful of states still issue them. Partners in a civil union cannot file federal taxes jointly, may not qualify for Social Security spousal benefits, and cannot sponsor each other for immigration. That federal gap is the single most important thing to weigh before choosing a civil union over marriage.
Why an Opposite-Sex Couple Might Choose This
After the Supreme Court legalized same-sex marriage nationwide in 2015, most states phased out civil unions or stopped issuing new ones. A few kept them available to all couples regardless of sex. For a man and woman who could legally marry, choosing a civil union instead is almost always deliberate.
The reasons tend to be personal. Some couples object to the historical gender roles tied to marriage as an institution and want a framework that feels more egalitarian. Others want legal recognition of their relationship without the cultural or religious weight of marriage. A few have practical reasons, such as preserving means-tested government benefits that would change on marriage: certain programs like Medicaid count a spouse’s income but may treat a civil union partner differently. Whatever the motivation, the trade is the same. You accept significantly fewer federal protections in exchange for a status that fits your life better.
What a Civil Union Gives You Under State Law
Within the state that issues it, a civil union typically puts partners in the same legal position as married spouses. The exact scope depends on the state, but the usual package includes:
- Property rights, including joint ownership of assets, shared responsibility for debts incurred during the union, and equitable division if the union ends.
- Inheritance rights under the state’s intestacy laws, the same as a surviving spouse would have.
- Hospital visitation and authority to make medical decisions for an incapacitated partner.
- Shared custody, guardianship, and access to adoption on the same terms as married couples.
- A legal obligation to support each other financially during the union, and potential maintenance if it ends.
- Spousal privilege against being forced to testify against each other, and access to domestic violence protections.
The important phrase is “under state law.” These protections exist inside the issuing state’s legal system. They do not reach federal programs, and they can disappear if you move to a state that does not recognize civil unions.
What the Federal Government Does Not Recognize
The IRS defines “spouse” and “marriage” in a way that specifically excludes civil unions. The regulation says those terms “do not include individuals who have entered into a registered domestic partnership, civil union, or other similar formal relationship not denominated as a marriage.”1GovInfo. 26 CFR 301.7701-18 – Husband and Wife The 2022 Respect for Marriage Act did not change this. It requires federal recognition of valid state marriages, but only of relationships “denominated as a marriage.”2Congress.gov. H.R.8404 – Respect for Marriage Act That one definitional choice ripples through every federal program tied to marital status.
Federal Income, Gift, and Estate Taxes
Civil union partners file federal income tax returns as single individuals, or as head of household if they qualify. They cannot use “married filing jointly” or “married filing separately.” The IRS has stated this plainly: because civil union partners “are not married under state law” for federal purposes, married filing statuses are unavailable.3Internal Revenue Service. Answers to Frequently Asked Questions for Registered Domestic Partners and Individuals in Civil Unions
The gift and estate tax consequences are larger than most couples realize. Spouses can transfer unlimited assets between themselves during life and at death with no federal gift or estate tax. Civil union partners get no unlimited marital deduction. Transfers above the annual gift tax exclusion ($19,000 per recipient in 2025) count against the giver’s lifetime exemption, and assets left to a surviving partner face the full estate tax calculation. For couples with significant wealth, this one difference can run into hundreds of thousands of dollars.
Some states let civil union partners file state tax returns jointly. The federal return still has to go in separately.
Social Security
Whether a civil union partner can collect Social Security spousal or survivor benefits depends on where the wage earner lives. The Social Security Administration treats civil unions as “nonmarital legal relationships” and runs a specific test: it looks at the intestacy laws of the state where the wage-earning partner is domiciled. If that state’s inheritance laws would treat the civil union partner as a surviving spouse, the SSA treats the relationship as a marriage for benefits.4Social Security Administration. GN 00210.004 – Nonmarital Legal Relationships If the state would not grant those inheritance rights, no spousal or survivor benefits are available.
Even when benefits apply, the relationship has to meet duration requirements. Spousal benefits require at least one year. Survivor benefits require nine months. The SSA counts from the date the couple entered the civil union.4Social Security Administration. GN 00210.004 – Nonmarital Legal Relationships
Immigration
Civil union partners cannot sponsor each other for immigration benefits. USCIS does not recognize civil unions as marriages for visa petition purposes.5U.S. Citizenship and Immigration Services. USCIS Policy Manual Volume 6, Part B, Chapter 6 If one partner is a U.S. citizen or permanent resident and the other needs status, only a legal marriage opens the door to a family-based petition.
Family and Medical Leave
The federal Family and Medical Leave Act lets eligible employees take up to 12 weeks of unpaid, job-protected leave to care for a spouse with a serious health condition. The statute defines “spouse” as “a husband or wife,”6Office of the Law Revision Counsel. 29 U.S. Code 2611 – Definitions and the implementing regulation ties that to marriage recognized under state law. The regulation covers same-sex marriages and common-law marriages, but not civil unions.7eCFR. 29 CFR 825.122 – Definitions of Spouse and Related Terms A civil union partner who needs time off to care for a seriously ill partner has no federal FMLA protection. Some states provide broader leave rights under their own laws.
Retirement Plan Division
When married couples divorce, a Qualified Domestic Relations Order lets one spouse receive a share of the other’s retirement plan. Federal law limits QDRO alternate payees to a “spouse, former spouse, child, or other dependent of a participant.”8U.S. Department of Labor. QDROs Chapter 1 – Qualified Domestic Relations Orders: An Overview Civil union partners are not “spouses” under federal law, so they cannot use QDROs to divide employer-sponsored retirement plans governed by ERISA. If the relationship ends, one partner can be shut out of what is often the couple’s largest asset.
What Happens If You Move
This is where civil unions cause the most practical trouble. A marriage from any state is recognized in every other state and by the federal government. A civil union has no such guarantee. If you move to a state that does not recognize civil unions, your legal status may effectively vanish. Property rights, healthcare decision-making authority, inheritance rights — the protections you relied on can lapse the moment you cross the state line.
Dissolution gets harder in the same situation. Most states require at least one partner to be a resident before their courts will handle the case. If your new state does not recognize civil unions, its courts may refuse to dissolve one. Some issuing states let non-residents return to file for dissolution where the union was created, but that means traveling back and often hiring an attorney in a second state. Until a court formally ends the union, both partners remain legally bound and cannot marry or enter a new civil union without bigamy issues.
How to Enter a Civil Union
The process looks like getting a marriage license. Both partners apply in person at a local government office, usually the county clerk, in a state that offers civil unions. They provide identification and proof of age and pay a licensing fee. Both must be at least 18. Most states also prohibit civil unions between close relatives and between people already in an existing marriage or civil union.
After the license is issued, the civil union is solemnized in a ceremony led by someone authorized under state law, which usually includes judges, clergy, and other designated officials. The completed certificate is then filed with the state. Waiting periods and ceremony requirements vary.
Couples can sign a written agreement before the union that defines how property, debts, and financial obligations will be handled during the relationship and if it ends. These agreements function like prenups and generally must be in writing, signed voluntarily, and based on full financial disclosure. They cannot override a court’s authority over child custody or child support.
How to End a Civil Union
Dissolving a civil union requires a court proceeding, like a divorce. One partner files a petition in the appropriate court, and the process from there tracks divorce closely. The court divides property and debts acquired during the union, decides whether either partner will pay maintenance, and if there are children, sets custody and child support based on the best interests of the child.
Cost and timeline depend on whether the dissolution is contested. When both partners agree, it can move quickly. When they do not, cases can run for months and legal fees climb accordingly. Court filing fees typically run a few hundred dollars before attorney costs. Planning for the possibility of a move, and addressing it in a pre-union agreement, can save real frustration later.
Civil Union vs. Domestic Partnership
The two terms get used interchangeably but mean different things. A civil union generally delivers the full state-law equivalent of marriage. A domestic partnership varies more by state. Some domestic partnerships closely mirror marriage; others provide only narrow benefits like hospital visitation or health insurance eligibility, and a few jurisdictions limit them to couples where at least one partner is above a certain age.
Both share the same federal ceiling. Neither counts as marriage under federal law, so neither delivers federal tax benefits, Social Security spousal protections, immigration sponsorship, or FMLA coverage.3Internal Revenue Service. Answers to Frequently Asked Questions for Registered Domestic Partners and Individuals in Civil Unions For a man and woman weighing the options, only marriage opens the full set of legal protections at both the state and federal level. The question is which trade-offs you can live with.