Statistics Canada says the country's birthrate has fallen to its lowest level in history, in large part because of the decline of something else: income.

In 1997, the rate reached 1.55 children per woman, a decrease researchers blame mainly on steadily shrinking take-home pay earned by young couples.

Agency researchers Alain Belanger and Laurent Martel conclude that financial constraints are preventing Canadians from producing enough children -- 2.1 per woman -- to replace the population as it dies off.

The previous trend of having at least a couple of kids is a luxury most new parents simply can't afford, according to the study.

One big factor is the growing number of women who make incomes as big, if not bigger, than their husbands. Taking time off to have children is more costly for these couples than for their parents one generation ago.

If the new trend continues, the StatsCan report predicts the country's fertility rate will be only 1.3 children per woman by 2010.

University of Toronto scientist Jack Wayne says other research has suggested that a lack of money is one of the major reasons couples in industrialized countries use contraceptive technology.