What is the significance of Allah Almighty's saying: "He bestows female (offspring) upon whom He wills, and bestows male (offspring) upon whom He wills; or He combines them, males and females, and He renders whom He wills barren"?

Allah Almighty is the Owner of the heavens and the earth. He grants males and females to whomever He wills, and He makes whomever He wills barren. This is according to His knowledge, power, and wisdom. The servant must be content with Allah's decree and destiny, for Allah only decrees good for the believer, whether it be a bestowal or a withholding, happiness or a trial. For a bestowal can be a withholding, and a withholding can be a bestowal, and a trial can be a mercy. Allah may withhold something from His servant to give him something better in return, as happened with the boy whom Al-Khidr killed by Allah's command, so that Allah might replace him with someone better for his parents. Allah tries His servants with withholding and bestowing to see whether they are thankful and patient or not. Whoever is granted gratitude and patience has been granted all good.