Zamierzenia prokreacyjne a możliwość ich realizacji w kontekście czynników biologicznych

The article presents both theoretical and empirical aspects of studies on fertility intentions in the context of factors shaping fecundity. In most contemporary societies couples declare their preference for two children. These declarations stand in opposition to registered total fertility rates, both period and cohort rates, which rarely reach value of 2 in Europe. The gap between fertility intentions and their realization might be partially explained by the impact of reproductive ageing (biological factors) which may play an increasingly significant role due to postponement of childbearing. A natural pattern of a decrease in fecundity over age might influence on reproductive outcome of women who postpone to conceive a child, and consequently results in an increased risk of involuntary childlessness or lower parity progression ratios. The data coming from the Generations and Gender Survey in Poland (GGS-PL) makes it possible to check the main hypothesis about an age-specific decrease in fecundity, which is manifested by a prolonged waiting time to pregnancy. The data were collected via the retrospective questions included into the GGS-PL questionnaire. Results show that there is a significant increase in waiting time to pregnancy among women older than 34 years. This finding supports theoretical predictions concerning the age-related decrease in fecundity. Its relevance is discussed by referring to explanations of the gap between fertility intentions and completed fertility in terms of voluntary and involuntary childlessness, as well as biological factors related to reproductive ageing.