Some prayers would be considered unreasonable, e.g., asking Allah to turn the Earth into cheese (as a silly, proof of concept example). In these settings, we can expect Allah to be unresponsive to the prayer, and it may even be viewed negatively. As such, I expect one should only pray about matters for which it is feasible for Allah to answer. This leads to the conundrum as to which prayers are worthwhile. In this question, I want to focus on infertile women.
Question: Is it reasonable for an infertile woman to pray to bear a child?
It would entail praying for a miracle, which might be considered unreasonable due to being an excessive request.
Allah answered such a prayer from the Prophet Zechariah:
I fear evil from my kinsmen after I am gone; and my wife is barren, so grant me an heir out of Your special grace, one that might be my heir and the heir of the house of Jacob; and make him, Lord, one that will be pleasing to You. Quran 19:5-6
So We accepted his prayer and bestowed upon him John, and We made his wife fit (to bear a child). Verily they hastened in doing good works and called upon Us with longing and fear, and humbled themselves to Us. Quran 21:90
However, there is a distinction due to Zechariah being a prophet.