The fertility rate is calculated from the number of live births of children over the female population aged between 15 and 49. Demographers have been able to estimate what a natural fertility rate could be. A natural fertility rate occurs when birth control practices are not deliberately carried out, although practices that have incidental impact on the fertility of women may be done (breast feeding for example). Various factors may affect the fertility rate, even in the absence of contraception or abortion, and explain the wide fluctuations of the rate that may be found over time or place. We only address the most important factors here, as they especially impacted on Quebec.
A first factor that served to reduce the fertility rate, and hence the birth rate, is age. Greater fertility is associated with a younger age. Beyond a certain age, which may vary from individual to individual, fertility declines rapidly until a point when the woman would become sterile. For some reason, a territory, or a given population, may have an older population, and hence lower fertility and birth rates. Areas of emigration are frequently in such a position as the young are more likely to be mobile, leaving behind an older population. To illustrate the point in the absurd, one would assume the fertility rate to be nil in an old folks home, or in a retirement community. In practice, if nearly all of the female population in the 15-39 range was to leave an area, the resulting fertility rate for that area would be very low.
A second important factor affecting the fertility rate, a factor important in Quebec until at least the Quiet Revolution, is the marriage rate [number of marriages in a year per thousand people]. In a traditional Catholic society, such as Quebec was for a long time, sex was only permissible within marriage. Although there was always a proportion of children born out of wedlock, such instances were statistically rather small. Thus, anything that happened that made people put off marriage, resulted immediately in decreases of fertility and birth rates. Such was the case in Quebec during the Great Depression [see the graph in the statistics section] when young people could not find employment and consequently put off marriage. A lower marriage rate can be caused by a variety of things. Some societies, or areas, may have a higher incidence of celibacy, and hence have a lower fertility rate. Acceptability of remarriage, after the death of a spouse, also affects the marriage rate. Some culture, or classes, have very late marriages. The later the marriage the lower the number of children born. A Canadian demographer was able to calculate that women from New France who married before 1700 had the following number of children according to their age at the time of marriage:
Further, the fertility rate may be affected by a number of situations and practices: contraception and abortion are among these, as are ill health, malnutrition, long-term breast feeding, sexual abstinence and coitus interruptus.
a specific discussion of Quebec population issues, see Birth
1999 Claude Bélanger, Marianopolis College