Is It Illegal to Marry Your Cousin in Pennsylvania? Here’s What the Law Says

Marriage laws in the United States vary by state, especially when it comes to unions between close relatives. One question that often arises is whether it is legal to marry your cousin in Pennsylvania. This topic is complex, blending legal definitions, historical roots, public policy, and personal values. In this comprehensive exploration, we’ll unravel Pennsylvania’s laws on cousin marriage, compare them to other states, touch upon health and genetic risk factors, and explore possible alternatives.

Defining Cousin Marriage

Cousin marriage refers specifically to a marital union between first cousins—individuals who share a grandparent. In legal terms, public policy in some places restricts marriages between “collateral relatives” within closer degrees of kinship due to potential genetic risks and historical taboos. In Pennsylvania, the restriction extends to first cousins—those who are as closely related as you can be without being direct ancestors or descendants.

Historical Context: Marriage Laws in America

During the 19th century, a wave of cousin-marriage prohibitions swept across the United States. Many of these laws emerged post-Civil War, driven by a growing interest in public health, morality, and eugenics. However, modern genetic studies have shown that the increased risk of birth defects in children of first-cousin couples is modest—around 2–3 percent above baseline risk, similar to the increased risk from advanced maternal age. Despite this, approximately half of U.S. states still prohibit marriage between first cousins, often due to longstanding precedent rather than contemporary science.

Pennsylvania’s Law on Cousin Marriage

In Pennsylvania, the law is clear: first cousins are not eligible to marry. State statutes define prohibited degrees of consanguinity, and the restriction extends to blood relatives up to and including first cousins, regardless of whether the union is between cousins through one parental side or both. This means Pennsylvania will not issue a marriage license to first cousins.

However, the law classifies such marriages as voidable rather than criminally prohibited. In legal terms, a marriage is voidable if it can be annulled through legal action, usually initiated by one of the spouses. Without such action, the marriage remains legally valid, provided it wasn’t dissolved during the lifetimes of the parties.

The Legal Implications: Void vs. Voidable

It’s important to distinguish between “void” and “voidable” marriages:

Void marriages are legally dead on arrival—treated as if they never existed (e.g., relationships between direct relatives).
Voidable marriages, such as cousin marriages in Pennsylvania, are considered legal unless someone challenges and annuls them.

A voidable marriage might still carry weight for property rights, inheritance, taxes, or spousal benefits if neither spouse seeks annulment. That said, Pennsylvania’s refusal to issue marriage licenses to first cousins forces them into a legal limbo: they can’t get married there, but if they do elsewhere, the marriage may continue unchallenged in Pennsylvania.

Comparisons With Other States

Nationally, regulation of cousin marriage is far from uniform:

24 states prohibit first-cousin marriage outright.
18 states allow it without restriction, including California, New York, Massachusetts, and New Jersey.
8 states allow it under certain conditions, such as age limits, sterilization requirements, or genetic counseling.
Pennsylvania is one of the 24 states that forbid such unions locally.

Some states criminalize incestuous marriages, but Pennsylvania does not criminalize cousin marriage—it is simply disallowed for license issuance.

What About Out-of-State Cousin Marriages?

A cousin couple can legally marry in a state where it is permitted—say, New Jersey, where there are no prohibitions. The bigger question becomes: will Pennsylvania recognize that foreign marriage if the couple moves back?

Pennsylvania follows the general legal principle known as lex loci celebrationis, which means marriages valid where performed are generally valid elsewhere, unless they violate the strong public policy of the home state. In practice, Pennsylvania appears to tolerate recognition of out-of-state cousin marriages, though it continues to refuse in-state license issuance. So, if a pair of first cousins marry legally elsewhere, Pennsylvania is unlikely to invalidate their marriage retroactively—especially if no one seeks annulment.

Immigration, Cousin Marriage, and PA Domicile

The issue becomes even more complex regarding immigration. U.S. Citizenship and Immigration Services (USCIS) requires a couple filing a spousal petition (I-130) to prove their marriage is valid at the time of filing, based on the petitioner’s legal domicile. If you’re living in Pennsylvania—a state that does not permit cousin marriage by license—you cannot file using that marriage while residing in Pennsylvania. However, if you establish domicile in a state like New Jersey or New York and then marry there, USCIS will generally recognize the marriage as valid, even if you later move back to Pennsylvania.

In short: USCIS eligibility depends on where you live, not necessarily where the marriage occurred. Pennsylvania couples who marry legally out-of-state can navigate immigration pathways, assuming they meet the residency requirements elsewhere.

Health and Genetic Considerations

Public concern over cousin marriage traditionally revolved around genetic risks. While compared to non-related couples, the risk of recessive genetic disorders is somewhat elevated—roughly 2–3 percent higher—the overall absolute risk remains relatively low. For many couples, genetic counseling can help assess and manage the risk effectively.

Globally, around 20 percent of marriages are between first cousins, particularly in parts of the Middle East and South Asia. Even in Western countries such as the U.K. and parts of Europe, there was no historical prohibition until the early 20th century. Today, health professionals typically support informed choice, not blanket bans, encouraging individuals to weigh cultural customs, family dynamics, and health considerations.

Cultural Perception and Social Stigma

Beyond the legal and scientific dimensions, marrying your cousin often carries cultural stigma in the U.S. For many families, the idea violates deeply held norms around taboo relationships. While legality governs formal status, acceptance remains a separate challenge. Cousin couples might face misunderstanding or social judgment, influencing their personal and community interactions.

However, others view it through a cultural lens, highlighting the normalcy of cousin marriage in different societies and historical periods. Some argue that if genetic risk is moderate and manageable, prohibitions may reflect outdated prejudice more than science.

Alternatives and Workarounds

Couples wishing to marry legally despite Pennsylvania’s restriction can consider several strategies:

Marry out-of-state in a jurisdiction that permits first-cousin marriage (e.g., New Jersey, New York, Massachusetts).
Establish domicile in that state before filing for marriage and during any required residency period.
Seek annulment or challenge voidability in Pennsylvania only if a legal issue arises.
Pursue non-marital arrangements such as cohabitation, domestic partnerships, or other legal agreements (though these may offer limited protections).

Each route carries its own benefits and limitations regarding taxes, inheritance, health insurance, and parental rights. Understanding these trade-offs is vital.

Key Takeaways

Pennsylvania bars first-cousin marriages by refusing to issue licenses, but does not criminalize them.
Such marriages are considered voidable, meaning they may continue legally if not challenged.
Individuals may marry legally in another state, and Pennsylvania typically recognizes such unions.
Immigration benefits depend on residency in a state where cousin marriage is allowed at filing time.
Genetic risk is elevated by a modest degree; genetic counseling can help couples make informed decisions.
While social stigma exists, legal and cultural landscapes are changing, and acceptance varies.
Alternatives like cohabitation or legal agreements may offer protections with fewer barriers.

Conclusion

Marrying your cousin in Pennsylvania presents a unique legal paradox. While the state prohibits issuing marriage licenses to first cousins, it does not criminalize or automatically void such marriages, treating them as voidable instead. Pennsylvanians can legally marry cousins by going out-of-state, and those marriages are usually respected upon their return.

It’s essential to consider both legal pathways and personal implications—whether for immigration, inheritance, social acceptance, or genetic health. Married-to-cousin couples should consult legal and medical professionals, especially if they plan to navigate complex systems like USCIS or intend to start a family.

Ultimately, the legality of cousin marriage in Pennsylvania hinges on where you marry, where you live, and whether anyone challenges your union. With thoughtful planning and informed decision-making, cousin-couples can navigate these waters confidently and with clarity.