Not Necessarily…
The first command of God to humanity is “be fruitful and multiply” (Genesis 1:28), and He wasn’t speaking of agriculture and mathematics. God instills in us a primordial impulse for children — children are a blessing and should be viewed as such. Indeed, when Pope Saint Paul VI wrote Humanae Vitae, he stated: “(L)ove is fecund. It is not confined wholly to the loving interchange of husband and wife; it also contrives to go beyond this to bring new life into being” (Humanae Vitae 9). Obviously, children are necessary for the continuation of the humanity.
Nevertheless, this is not an absolute command. Jesus says some people “renounce marriage for the sake of the Kingdom” (Matthew 19:12) and St. Paul says those who are unmarried “are concerned about the Lord’s affairs” (1 Corinthians 7:32ff). One could speak of the necessity for spiritual motherhood and fatherhood, but that would be for another topic.