World population 'on the rise'
People keen to slow down the increasing world population may want to ensure they use condoms when participating in sexual activity.
New estimates from the Population Division of the Department of Economic and Social Affairs of the United Nations have shown more than seven billion people will be alive later this year - one billion more than in 1999.
Moreover, it is anticipated a further 2.3 billion people will be added to this number between now and 2050, while it has been forecast the world population will swell to 10.1 billion by 2100.
The review, published in the journal Science, suggests nearly all of the projected increases will take place in less developed regions, such as Africa.
David Bloom, Clarence James Gamble Professor of Economics and Demography at the Harvard School of Public Health - which was founded in 1922 - said: "Although the issues immediately confronting developing countries are different from those facing the rich countries, in a globalised world demographic challenges anywhere are demographic challenges everywhere."