To get married is in one’s control but having children is not in one’s control. While adopting the means is within our control, seeing the fruits of the means is out of our control. Allah Ta’ala alone controls everything. A person of Imaan will never get angry nor blame someone for something which is not in that person’s control. The doctor can only explain to the couple the possible reasons for them not having children. Thereafter he may prescribe various medical treatments. His expertise ends at this point. He cannot guarantee the couple that they will have a child. At times we get so engrossed in adopting the various means, that we unconsciously completely forget our Allah Ta’ala, the sole creator and controller of everything.