No Children In Paradise
Adam and Eve were created as young adults i.e. Adam was immediately able to care for the garden and Eve was immediately able to become Adam's wife.
"2:7 And the LORD God formed man of the dust of the ground [see Christ The Creator], and breathed into his nostrils the breath of life [see The Spirit Of God]; and man became a living soul [see Where Is Your Soul?] ... 2:15 And the LORD God took the man, and put him into the garden of Eden to dress it and to keep it." (Genesis 2:7,15 KJV)
"The son shall not bear the iniquity of the father, neither shall the father bear the iniquity of the son"
As plainly stated in the verses quoted above, Adam and Eve were physically capable of having children while they were in Eden, but before they would have done so, they had themselves cast out of the Garden. Although the first two humans were "born" in God's world, their children would be born in Satan's world.
"3:14 And the LORD God said unto the serpent, Because thou hast done this, thou art cursed above all cattle, and above every beast of the field; upon thy belly shalt thou go, and dust shalt thou eat all the days of thy life: 3:15 And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.
Children were thereafter born to Adam and Eve - children who never knew the innocence of the first two, before they too had become immersed in Satan's world.
"4:1 And Adam knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man from the LORD. 4:2 And she again bare his brother Abel. And Abel was a keeper of sheep, but Cain was a tiller of the ground." (Genesis 4:1-2 KJV)
The paradise that is coming (see the Fact Finder question below) will be the Kingdom of God, on earth, in which repentant people, after living sufficient time to demonstrate their repentance (something that children, by definition, need more time to do - see Why Isn't Infant Baptism Valid?), will be "born again" as spirit (see Born Again, How and When?).
One reason that the later resurrection (see Resurrections and When Will You Be Judged?) will be physical is to accommodate all of the humans who did not receive the means to repent during their lifetimes (see The Cure For The Carnal Mind).
The other reason is to give children, even of repentant parents, the time that they need to make an adult decision about their salvation (a future situation where the parents will have become spirit at the first resurrection, while their children are yet physical, either from the second resurrection, or of being alive on the day of Christ's return - with the parents still there for them, either way). The LORD isn't going to give eternal life to those who have yet to make up their own minds, after they have reached an age when they are accountable.
"18:20 The soul that sinneth, it shall die. The son shall not bear the iniquity of the father, neither shall the father bear the iniquity of the son: the righteousness of the righteous shall be upon him, and the wickedness of the wicked shall be upon him." (Ezekiel 18:20 KJV)