Experts on family law and advocates for women say that early marriage imposes social, educational and financial burdens on teenage girls. Often, the marriages are arranged for girls by families whose religious and cultural customs support the practice. Girls are often wed to older men — even to relatives, like cousins, from abroad who are in search of green cards that allow them to live permanently in the United States.

Across the country, laws allowing early nuptials are common. A majority of states allow 16- and 17-year-olds to marry, and more than two dozen other states have no statutory minimum age at all. Since 1929, New York has permitted 14- and 15-year-olds to marry with judicial and parental approval, and 16- and 17-year-olds to marry with only parental consent.

Between 2000 and 2010, nearly 3,900 minors were married in New York. Only a handful of boys and girls typically marry as young as 14 or 15, however. In 2010, for instance, only two 14-year-old boys and one 15-year-old girl were married statewide. But the numbers rise quickly for slightly older teenagers. That same year, 50 girls and six boys who were 16 said marriage vows in New York.

Early marriage carries other costs, advocates say. A girl can marry at 14, but cannot legally divorce until 18. The new law will mandate that a 17-year-old who marries will also be able to divorce. And shelters for victims of domestic violence generally do not accept anyone under 18.

Last month, Gov. Chris Christie of New Jersey, a Republican, conditionally vetoed a bill that would have banned marriage for those under 18. He said the legislation, which passed both houses of the Legislature by strong margins, did not “comport with the sensibilities” or “religious customs” of some state residents. In New Jersey, 16- and 17-year-olds may marry with parental permission, while younger teenagers can obtain marriage licenses with a judge’s order.