Recommending childbearing and increasing the number of followers is a common teaching in all religions. This recommendation is also important in terms of economy as well as the role of manpower in defense.
Islam calls on its followers to increase the population of believers. There are many verses in the Holy Quran about children. They refer to children as divine blessing, that like other blessings, should be used on the path of perfection and salvation.
Verse 78 of Surah An-Nahl says: “Allah has given you wives from among yourselves, and has given you and your wives, sons and grandsons and He has provided you with good things. What, do they believe in vanity; do they disbelieve in the favor of Allah?”
So having the ability to have children is God’s favor. The Holy Quran says about Prophet Zakariya (Zechariah): “Zakariya prayed, ‘Lord, do not leave me alone without offspring, although you are the best heir.’” (Surah Al-Anbiya, verse 89)
In another verse, God says: “Zakariya prayed to his Lord there, saying, ‘Lord, grant me, by Your Grace, virtuous offspring. You hear all prayers.’” (Surah Al-Imran, verse 38)
The Quran says this prayer by Zakariya was answered: “So We answered him, and gave him John, curing his wife (of sterility).” (Surah Al-Anbiya, verse 90)
These verses show that children help their parents in religion and in worldly matters and that it is the path of prophets of God to pray to God for virtuous offspring.