Tying the knot may be taking a few more years even though women are aware that their fertility peaks when they are 25. Specialists will say that child bearing should be done by 35 otherwise the woman may experience difficulties in being able to conceive and their might be anomalies that can occur like certain birth defects including cardiac ones in the infant.
Cultures vary as far as the age of consent for marriage. In India, young teenagers are still encouraged to marry. The girl may think that a boy of 21, who is hardly an adult, is ready while he might consider a girl of 16 to be ready. Here most of us think that that is still to early, she is just a few years away from puberty and has a minimal understanding of the responsibilities of child bearing and raising a family.
Young parents were also common in Italy before the Second World War when families wanted to be more self-sufficient and be able to turn their agricultural work into a profitable business. Then there wasn’t the crowding of top positions and high unemployment as now. This explains a recent decline in the birthrate because children will wait longer in order to have a better job to afford child rising.
In North America and specifically Quebec families were much larger and people tended to marry at similar ages to what they do in India too. The logic was that a greater number of kids meant a larger harvest but the downsize was the family could not afford to educate all or any of its offspring and people began to see better job opportunities in cities. There the birth rate declined; there was no reason to have as many children as rural needs were absent but also because the cost of living rose with the urban development. Children decided to wait longer too before marrying or having a family, to guarantee a better lifestyle for themselves and their offspring. But the biological clock is still there and for the most part women can only conceive up until a certain moment, without any ill consequences.