How to stop child marriage? Punish husbands, parents and wedding guests.

The president of the tiny West African nation of Sierra Leone signed a law Tuesday banning marriage for children 18 and under and imposing stiff fines on adult spouses, a victory for activists who have long fought to eradicate the widespread practice.

The new legislation goes further than many other similar laws in Africa, experts say, by punishing not only the spouse but also people who facilitate the marriage, such as the parents, the registrar and even the guests.

There were approximately 800,000 girls under the age of 18 who were married in Sierra Leone, UNICEF reported in 2020, which is about a third of the country’s girls. Half were married by age 15. About 4 percent of boys are married by age 18, according to Human Rights Watch.

Under the new law, those who were married as children can seek financial compensation. They also have a way to leave their marriage: file a petition for annulment.

Betty Kabari, a researcher at Human Rights Watch who focuses on women’s rights and sexual health in Africa, praised the approach of punishing those who encourage marriage. She said: “The strongest aspect for me is that you see that a child is not getting married in isolation.”

How prevalent is child marriage?

At least 12 million girls under the age of 18 are married every year, according to the United NationsMore than 650 million girls and women were married as children.

South Asia has the largest number of child brides, about 290 million people, or 45 percent of the global total. Sub-Saharan Africa follows with approximately 127 million people, 20 percent.

According to a map of child marriages Maintained by Girls Not Brides, a global organization working to end the practice, 16 of the 20 countries with the highest rates are in Africa.

A report published this year by Equality Now A study of 20 countries in Africa found that only a few countries had a complete ban, and many countries were not adequately enforcing these bans.

What problems might you encounter when you get married so young?

Child marriage often leads to girls dropping out of school. Early pregnancies can cause long-term injuries and trauma.

Sierra Leone is one of the deadliest places to give birth, which is even more dangerous for teenagers.

“They are forced to be adults before they are adults,” said Kadijatu Barrie, 26, a student and program coordinator at Strong Girls Evolution, a networking organization for women in Sierra Leone, among other groups.

Ms Barrie said her family pressured her to marry when she was 10, and she was disowned by her father when she was 15 for refusing. She said she feared she would have to leave school.

“Because of all this, we have fewer educated women,” she said.

Many face additional complications from another widespread cultural practice in the country: female genital mutilation, which is considered a human rights violation by the World Health OrganizationAbout 61 percent of girls in Sierra Leone between the ages of 15 and 19 have experienced female genital mutilation, which can cause serious problems during childbirth.

How does the ban work in Sierra Leone?

Under the new law, which took effect Tuesday, people who marry children could face up to 15 years in prison or more than $5,000 — a stiff penalty in a country where per capita growth in domestic product is expected to be about $433 by 2023. according to World Bank data.

The law does not only apply to marriage. It also prohibits cohabitation, where adults live together with children and have a sexual relationship with them.

Parents are also not allowed to consent to the marriage of a child. Officiants are not allowed to officiate. Guests are not allowed to attend the ceremony. In fact, anyone who “aids or abets” the marriage can face up to 10 years in prison or a fine of about $2,500, or both.

The ban is part of a broad initiative in Sierra Leone to promote girls’ rights by keeping them in school and protecting them from genital mutilation.

President Julius Maada Bio said 22 percent of the national budget in education and brought more women into government. He and his wife, Fatima Bio, pushed for a ban on child marriage.

“I have always believed that the future of Sierra Leone is female,” Mr. Bio posted on social media after signing the law with his young daughter at his side.

Nerida Nthamburi, Head of Africa Engagement at Girls Not Brides, said:

“We want to see Sierra Leone as a leader on the continent that can influence other countries.”

What are the obstacles to the ban?

In other countries, criminalising child marriage has led to an illegal practice, Ms Nthamburi said, closing communities and leaving girls with even less protection from the practice.

For the law to have real impact, Sierra Leone’s authorities will need to build lasting relationships with communities, researchers and experts say, especially in rural areas, where child marriage is more common.

That would mean tackling poverty, which can lead families to marry off their daughters as children. It also means expanding efforts to educate communities about sexual and reproductive health.

Many women and girls would still have to go against their neighbors, their husbands and their families to refuse a marriage, petition to end the marriage or claim compensation.

Ms. Barrie was ostracized because she refused to resist pressure from her family. “They all came together and turned on me,” she said. “I became the worst person to them.”

She said she had tried to stop her younger sister from getting married when she was 14. But she had heard how Mrs. Barrie was vilified in the community. Her sister, talented at drawing, wanted to be a fashion designer.

“I couldn’t save her,” Mrs. Barrie said. “It’s still something I cry about.”

Joseph Johnson contributed to the reporting.