The way we live now is more unsettled. A woman graduate is reasonably established in a career in her late twenties and ready to think about marriage and children. It can happen, but the hazards along the road are many and there is not much room for error. The most serious problems relate to time.
The most obvious one is biological clock time. Medical infertility is around 5% for 20-year-olds, 10% for 30-year-olds, and pushing 20% for 35-year-olds, so anyone leaving decisions to the late thirties is taking a risk. Mr Right has to be identified, got up the aisle (or secular equivalent) and convinced he wants children, in a very few years. Learned discussions of these matters in terms of people’s strategies, choices, values and risk aversions tend to make the implicit assumption that normal people have a number of choices of potential partners. Everyone really knows that is not true. Finding someone worth marrying who thinks the same about oneself is simply difficult, and one is not notably unlucky if one has no such chance in a five-year period. Again, a woman married at 20 can have another try if necessary, but a 30-year-old graduate has to get it right first time. It is a tall order, given that towards half of marriages end in divorce.