British prime minister David Cameron wants female genital mutilation (FGM) and child marriages to stop globally within a generation, starting with Britain.
FGM - the partial or total removal of external female genitalia - is a tradition practised widely in many African and Muslim countries.
It is often justified as a means of suppressing a woman's sexual desire to prevent "immoral" behaviour.
Speaking at an international summit on the issue, in London, Mr Cameron announced new measures to eradicate the practice in Britain.
About 103,000 women, as well as 10,000 girls under 15 living in England and Wales have undergone female genital mutilation, according to estimates in a report by City University London.
Mr Cameron says it is an "abhorrent practice" and his government will spend 1.4 million pounds ($2.4 million) on the new prevention program.
Under the plan, it will be compulsory for doctors, teachers and social workers to report any cases of FGM in Britain.
FGM has been a criminal offence in Britain since 1985 but new legislation in 2003 introduced a maximum prison sentence of 14 years.
The 2003 act also made it an offence for British citizens to carry out or procure FGM abroad, even in countries where the practice is legal.
Mr Cameron says new laws would also see parents prosecuted if they fail to prevent their daughter undergoing such a practice.
"It's absolutely clear what we are trying to achieve ... and that is to outlaw the practices of female genital mutilation and childhood early forced marriage, to outlaw them everywhere, for everyone, within this generation," he said.
Hundreds of millions suffering worldwide
More than 130 million girls and women globally have undergone FGM and more than 700 million women alive today were children when they were married.
Mr Cameron says 21 countries have already signed an international charter to eradicate both practices, launched at the summit in London, and he is urging more countries to make it happen.
Ministers and officials from Pakistan, Somalia, Ethiopia, India, Bangladesh, Burkina Faso, Zambia and others have pledged to step up efforts to tackle both issues.
UNICEF warns that population growth, particularly in sub-Saharan Africa, means the number of FGM victims will soar and there will be no decline in the number of child brides unless global action is dramatically accelerated.
Mr Cameron says ending FGM and child marriage is a global challenge on par with eradicating poverty and tackling diseases.
"We are dealing with a preventable evil. This does not need to happen," he told the summit that attracted more than 500 delegates from 50 countries.
Malala Yousafzai, the Pakistani schoolgirl and girls' rights campaigner who was shot in the head by the Taliban in 2012, is also at the event.
She says getting girls into school is the best way to fight child marriage and FGM.
Malala says it is wrong to think that Islam is against women's education and empowerment and those who think so should go back to the Koran.