Almost 100 million girls "disappear" each year, killed in the womb or as babies, a study has revealed.

The report, "Because I am a Girl", exposes the gender discrimination which remains deeply entrenched and widely tolerated across the world, including the fact that female foeticide is on the increase in countries where a male child remains more valued.

The report highlights the fact that two million girls a year still suffer genital mutilation, half a million die during pregnancy - the leading killer among 15 to 19-year-olds - every 12 months and an estimated 7.3 million are living with HIV/Aids compared with 4.5 million young men. Almost a million girls fall victim to child traffickers each year compared with a quarter that number of boys.

Of the 1.5 billion people living on less than 50p a day, 70 per cent are female, with 96 million young women aged 15 to 24 unable to read or write - almost double the number for males.

While many of the most shocking figures in the Plan International report relate to developing nations, sexual discrimination is still prevalent in the north.

In the UK, two women a week are killed by current or former partners. The country also has the highest rate of teenage pregnancy in Europe and having a baby at a young age means women are more likely to miss out on education and slip into poverty. There has also been a substantial rise in obesity in young girls in the UK.

While girls in Britain often outperform boys in school, they are still victims of discrimination in the workplace. The report points out that a recent study found they were still woefully underrepresented in the boardroom, in politics and the courts. While the pay gap between young men and women is 3.7 per cent, it rises to 10.7 per cent for those in their thirties.

"Even if you look at the UK, life is still difficult for some minority girls," said Marie Staunton, chief executive of Plan UK. "More girls are going to university but then it flattens off. They have broken through the marble ceiling into management but not through the glass ceiling into the boardroom."

The "Because I am a Girl" campaign launched today highlights discrimination and will work towards improving gender equality worldwide. Designed to run until 2015, the campaign will also follow the lives of 125 girls born in 2006 until their ninth birthday. Today's report is the first in a series of nine studies by Plan International - a global child development agency.

Statistics show that 62 million girls are not even receiving primary school education while an estimated 450 million have stunted growth because of childhood malnutrition. "Why, in an era that saw the term 'girl power' coined, are millions of girls being condemned to a life of inequality and poverty?" the report asks.

Graça Machel, the children's rights campaigner from Mozambique, said: "The study shows that our failure to make an equal, more just world has resulted in the most intolerable of situations. To discriminate on the basis of sex and gender is morally indefensible; it is economically, politically and socially unsupportable."

© 2007 Independent News and Media Limited