STUDY: SEX FOUND MAIN CAUSE OF POPULATION GROWTH

Optimum Population Trust - Sex, not religious or cultural beliefs or the quest for economic security, is what increases family size and drives world population growth, according to one of the UK's leading authorities on family planning.

Conventional economic wisdom, which says that couples in poorer societies actively plan to have large families to compensate for high child mortality, to provide labour, and to care for parents in their old age, is wrong, Professor John Guillebaud will tell a conference on sustainable population today.

Economists overlook the fact that sexual intercourse is more frequent than the minimum needed for intentional conceptions, and that half of pregnancies worldwide are unplanned. Moreover, demand for contraception increases when it is available, irrespective of a society's wealth or child survival rates.

"Having a large rather than a small family is less of a planned decision than an automatic outcome of human sexuality," Prof. Guillebaud will say. "For a fertile couple, nothing is easier.". . .

Many environmentalists argue that greener lifestyles, and reducing consumption, are the key to solving environmental challenges such as climate change. However, Dr. Martin Desvaux will disclose details of research showing that even with an 80 per cent reduction in carbon emissions by 2050, the UK will be able to sustain only 37 million people. This will make the UK "extremely vulnerable in an uncertain world", he will argue. The UK's population, currently 61 million, is projected to rise to 77 million by 2050.

Even if Britain's population could be capped at 70 million, as suggested by the immigration minister, Phil Woolas, last year, there would still be up to 33 million too many people in the UK for long-term sustainability, according to Dr. Desvaux.

The conference will also hear that despite the likelihood of a world population crash as a consequence of inaction on overpopulation, 21 European countries are trying to raise their birth rates.

Prof. Guillebaud will argue that in both rich and poor countries, "something active needs to be done to separate sex from conception - namely, contraception. . .