Women in chains protest against child marriage at the New York Capitol in Albany. New York and other states are considering tightening laws that allow minors to marry with parental or judicial approval. © The Associated Press

Editor's note: This has been updated to reflect the New Jersey governor's veto.

Most Americans think of child marriage as a vestige of a bygone era. And yet in every state, people under 18 are allowed to marry.

Some states set minimum ages for brides and grooms — sometimes as low as 13 or 14 — and usually require the permission of a parent, judge, or both before a minor can wed. But laws in about half the states allow children of any age to marry, as long as they receive the proper permission.

That may be changing. This year legislators in 10 states have introduced bills to raise the marriage age. Proponents say updating marriage laws, which in many states are more than a century old, will help protect children from being pushed into marriages by parents and predators. Some lawmakers, disturbed by instances of pregnant girls heading to the courthouse to marry older men, argue that marriage licenses should not be given to men who have committed statutory rape.

Young brides who say they were forced down the aisle are backing the efforts, as are justices of the peace who say current law requires them to approve marriages between young girls and older men.

“Fourteen was just ridiculous,” said New York Assemblywoman Amy Paulin, a Democrat who sponsored a bill this year that would align the age for marriage with the state’s age of sexual consent, 17. Minors still would need parental and judicial permission to marry.

Proponents of raising the marriage age had some success in Virginia, where girls under 16 were permitted to marry if they were pregnant. A law enacted last year requires 16- and 17-year-olds to be given adult status from a court before they can marry.

But Republican Gov. Chris Christie vetoed a bill Thursday that would have made New Jersey the first state to outlaw marriage for anyone under 18. Under state law, people under 18 need parental permission to marry, and those under 16 must also have a judge’s consent.

In California, a Senate bill to eliminate the process that allows those under 18 to marry was weakened in committee this week after the American Civil Liberties Union (ACLU) of California said the measure unnecessarily intruded on the right to marry. The current version of the bill would require Family Court Services to interview both parties and a parent to ensure no one was being coerced to marry.

Kevin Baker, legislative director for the ACLU of California, said the group was concerned about forced marriage, “but we wanted to make sure we weren’t also sweeping in voluntary marriages.”

And in New Hampshire, where girls as young as 13 and boys as young 14 are permitted to marry with parental consent and a judge’s approval, legislators in March voted down a bill to raise the marriage age to 18. Critics said judges should be able to approve young marriages in exceptional circumstances, such as a pregnancy or in cases when someone is joining the military.

“It’s not that there’s a bunch of screwball legislators wanting 13-year-olds to get married,” said New Hampshire state Rep. David Bates, a Republican who voted against the bill. “I don’t think there’s any justifiable rationale to absolutely prohibit someone in those situations from getting that judicial waiver.”

In Missouri, where children as young as 15 can get married with a parent’s permission, state Rep. Jean Evans, a Republican, introduced a bill to raise the marriage age after hearing that counties close to the state’s borders were seeing more young women come in to get married. In one 2016 case, an Idaho man drove his 15-year-old daughter to Missouri so she could marry the 25-year-old man who had impregnated her. In 2014, the most recent year for which numbers are available, 158 16- and 17-year-olds and 23 children who were 15 or younger got married in Missouri, according to the state.

Her bill, passed by the House in March, would allow those under 18 to get married only after a judge approves it and determines there is no evidence of coercion. Those under 17 would not be able to marry someone older than 20, a relationship that could violate the state’s statutory rape law.

Jeanne Smoot with the Tahirih Justice Center, a gender equality group that has pushed legislation in several states, including New Hampshire, to raise the marriage age to 18, said people who want to marry someone young look for nearby states with looser laws where perhaps only one parent’s signature is required or where they may not have to face a judge.

“Certainly that’s the kind of destination wedding reputation no state should want, and yet they already have it,” Smoot said.

Child marriages represent a small share of total marriages in the U.S., but still number in the tens of thousands. Nearly 60,000 15- to 17-year-olds, nearly five out of every 1,000, were in marriages in 2014.

Those who marry as children face a unique set of potential legal complications, particularly if they want to leave the marriage. In some states, people under 18 are not permitted to get divorced. Most domestic violence shelters won’t accept people under 18. And because they are legally still children, those who try to escape a marriage may be returned by social services to the parents who approved the marriage in the first place.