Very few couples remain voluntarily childless.

"The secular decline of fertility, which reached its bottommost level between the two world wars, went together with a rise in permanent infertility that was sometimes, in the ideological atmosphere of the time, ascribed to physiological factors, but obviously indicated that some couples were refusing to have children. The signs of a similar pattern in present-day France are much more discreet. Having emerged relatively recently, it is difficult to quantify, but the main problem is that sterility therapy now makes it more difficult to define once and for all a level of infertility beyond which we can speak of ¿refusal to have children'. In an attempt to do so, [the author] uses an impressive range of tools: analysis of vital registration and census data, of ad hoc and general surveys, methods of estimation to fill in the many gaps, fertility models and so on. It is a useful reminder that the understanding of fertility behaviour goes beyond the mere interpretation of individual intentions." excerpt