(CNN) In 2018, child marriage remains a problem worldwide. Consider that each year, 15 million girls are married before the age of 18, according to Girls Not Brides, a global partnership committed to ending such marriages.

That's 28 girls every minute; 1 every 2 seconds. s

The consequences of getting married at a young age can be devastating. Marriage can rob girls of their childhood and compromise their development. They often pay a heavy price in not getting an education or access to proper health care and economic opportunities. Many become victims of domestic violence and grow up feeling disempowered.

India leads the world in the number of child marriages

More than 700 million women across the world were married as children, according to Girls Not Brides.

Child marriage occurs in every region in the world and affects all religions, ethnicities and cultures.

Niger has the highest rate of child marriage, while India has the highest number.

Yes, it happens in the United States

Few perceive the United States as a land where child marriage occurs. But it does.

"When you look at the laws and see the lack of protection for girls, you are stunned," said state Rep. Jeannette Nunez, sponsor of a bill that would ban all child marriages in Florida. "The average individual would not believe Florida, or any other state for that matter, does not have the laws."

Some 248,000 children were married in America between 2000 and 2010, according to Unchained at Last, a US nonprofit group that helps girls and women rebuild their lives after forced marriages. Some were as young as 10.

Abuse and pregnancy

A majority of child marriages in the United States involve girls marrying adult men. In many cases, the marriages involve an abusive situation or a pregnancy, according to the Tahirih Justice Center.

Sherry Johnson of Florida was made to marry her rapist when she was 11 . He was 20. She is now an advocate for ending child marriage in her home state.

"It's shocking and horrible that something like this could occur at the hands of people who were supposed to protect me," Johnson says."There were no other safety nets."

Donna Pollard of Kentucky was married at 16 to a man who abused her.

"People know it is exploitative but all of a sudden you put a marriage license in front of it, and that means it's OK," says Pollard, who also advocates on behalf of survivors. "Because people want to preserve families."

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Loopholes in the law

Every US state allows minors to get married either by setting an age floor below 18 or through parental consent and judicial approval.

"We recognize that children cannot consent to sex, so marriage laws are inconsistent with our sexual abuse statutes," says Sandy Skelaney of the Center for Women's and Gender Studies at Florida International University

In 2018, still a problem

The number of child marriages has been steadily declining in the United States. But not fast enough, advocates say.

In recent months, momentum has built around the issue and this year, more than a dozen states have introduced bills tackling child marriage, though not all would set an age floor of 18.