Nyaya - A prayer for a son and the loss of the husband.

पुत्रलिप्सया देवं भजन्या भर्तापि विनष्ट इति न्यायः

It takes its origin form a story that a certain woman worshipped a god with a view of being blessed witha son, unfortunately it so happened that she lost her husband. It is used to denote the loss of the cause while the effect is earnestly wished for. It is used to denote the absurdity of a wish or desire.