"Decades on, she is still unmarried without children - and not by choice ."
It IS by choice! ALL we are doing in our daily life is by choice! We make our decisions subconsciously, based on our momentary needs, wishes, feelings.
You can go to supermarket by two different ways. The way you have chosen on some particular day may turn over all your life.. it was YOUR choice to take this way..
.. so when it comes to having families and babies, it is definitely your choice! Are you busy with something else? You cannot get alone with your partner? You keep in mind "I still have time"? ... Well, it's all about priority...

Each one chose his/her life this way or another.. no one to be blamed..

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"What lies behind us and what lies before us are small compared to what lies within us."
Oliver Wendell Holmes