Allah Says in the Holy Quran Chapter 42 Surah Shuraa verses 49-50:
49 To Allah belongs the dominion of the heavens and the earth. He creates what He wills (and plans). He bestows (children) male or female according to His Will (and Plan).
50 Or He bestows both males and females, and He leaves barren whom He will: for He is Full of knowledge and power.

In light of the above Aayah of the Glorious Quran, it should be the belief of the believers, who truly believe in Allah and the Last Day, that the allotment of children is entirely upto Allah Subhanah. He gives males to whom He pleases, He gives females to whom He pleases, He gives males and females to whom He pleases, and if He Wills, He leaves some childless (as a test from Him).

If Allah Subhanah has put someone in a trial by not bestowing them with offspring; they should remain constant in their patience, and steadfast in their trial ordained by Allah Subhanah, and supplicate Allah Subhanah Alone to make their trial easy for them.

Allah says in the Holy Quran Chapter 2 Surah Baqarah verse 186:And if My servants ask you, O Prophet, concerning Me, tell them that I am quite near to them. I hear and answer the prayer of the suppliant, when he calls on Me. So let them respond to My call and believe in Me. (Convey this to them), perhaps they may be guided aright.

Allah Subhanah put the noble Prophet Zachariyaa (a..s.) to a similar test, and this is the supplication the noble Prophet (saws) made which was answered by Allah Subhanah, Who blessed him with a noble son, Prophet Yahyaa (a.s.).

Allah Says in the Holy Quran Chapter 21 Surah Anbiyaa verses 89-90:
89 And (remember) Zakariya when he cried to his Lord: "O my Lord! leave me not without offspring, though Thou art the best of inheritors.
90 So We listened to him: and We granted him Yahya: We cured his wife's (barrenness) for him. These three were ever quick in emulation in good works: they used to call on Us with love, and reverence, and humble themselves before Us.

Allah Says in the Holy Quran Chapter 19 Surah Maryam verses 2-9:
2 (This is) a recital of the Mercy of thy Lord to His Servant Zakariya.
3 Behold! he cried to his Lord in secret
4 Praying: "O my Lord! infirm indeed are my bones, and the hair of my head doth glisten with grey, but never am I unblest, O my Lord, in my prayer to Thee!
5 "Now I fear (what) my relatives (will do) after me: but my wife is barren: so give me an heir as from Thyself
6 "(One that) will (truly) represent me and represent the posterity of Yaqoob; and make him O my Lord! one with whom Thou art well-pleased!"
7 (His prayer was answered): "O Zakariya! We give thee good news of a son: his name shall be Yahya: on none by that name have We conferred distinction before."
8 He (Zackariyya) said: "O my Lord! How shall I have a son when my wife is barren, and I have grown quite decrepit from old age?"
9 He (Allah Subhanah) said: "So (it will be): thy Lord saith `That is easy for Me: I did indeed create thee before when thou hadst been nothing!' "