As the United Nations recognises a child born in Bosnia as the six-billionth
inhabitant of the planet, BBC News Online's special coverage looks at the threats posed by a crowded world:
Why we should worry If economic growth and associated consumption are left unchecked, catastrophe threatens: Dominic Casciani asks what we can do.
The planet feels the strain If you think of the earth as a Noah's Ark, a life-friendly
speck floating through space,
you will appreciate its passenger capacity is limited, writes Environment Correspondent Alex Kirby.
Case study: Madagascar Watch Roger Harrabin's report from Madagascar on the threats to the local ecosystem.
Your views Are there too many people in the world? Send us your views and read what you've said.
The sexual health minefield An estimated 114 million acts of sexual intercourse take place in the world every day: Mandy Garner looks at the continuing battles over family planning and sex education.
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