In another thread about babies going to heaven, a poster said "I cannot picture babies roaming around in hell."
The bodies of all who die do not go to hell (sheol) or heaven for that matter. The general resurrection has not yet taken place.
1 Thessalonians 4:13-18 (NKJV)
13 But I do not want you to be ignorant, brethren, concerning those who have fallen asleep, lest you sorrow as others who have no hope.
14 For if we believe that Jesus died and rose again, even so God will bring with Him those who sleep in Jesus.
15 For this we say to you by the word of the Lord, that we who are alive and remain until the coming of the Lord will by no means precede those who are asleep.
16 For the Lord Himself will descend from heaven with a shout, with the voice of an archangel, and with the trumpet of God. And the dead in Christ will rise first.
17 Then we who are alive and remain shall be caught up together with them in the clouds to meet the Lord in the air. And thus we shall always be with the Lord.
18 Therefore comfort one another with these words.
Jude 14-15 (NKJV)
14 Now Enoch, the seventh from Adam, prophesied about these men also, saying, “Behold, the Lord comes with ten thousands of His saints,
15 “to execute judgment on all, to convict all who are ungodly among them of all their ungodly deeds which they have committed in an ungodly way, and of all the harsh things which ungodly sinners have spoken against Him.”
Revelation 20:11-15 (NKJV)
11 Then I saw a great white throne and Him who sat on it, from whose face the earth and the heaven fled away. And there was found no place for them.
12 And I saw the dead, small and great, standing before God, and books were opened. And another book was opened, which is the Book of Life. And the dead were judged according to their works, by the things which were written in the books.
13 The sea gave up the dead who were in it, and Death and Hades delivered up the dead who were in them. And they were judged, each one according to his works.
14 Then Death and Hades were cast into the lake of fire. This is the second death.
15 And anyone not found written in the Book of Life was cast into the lake of fire.
Until then no one (except Christ himself) is bodily raised. 2 Corinthians 5:1-8 clearly speak our our disembodied spirits when we who believe go to be with him in death.
So... how old is the spirit that departs from a baby? ...from an adult?
We have to stop imposing the physical upon spiritual in our thinking and understanding. Babies do not wander around in hell or heaven. And when the Day of the Lord has come the bodies and spirits of believers will live on in ageless maturity as that of Adam the adult from day one of his existence. Those of the doomed, their bodies will be destroyed in the fire and their spirits will live on in suffering torment.
Malachi 4:3 (NKJV)
3 You shall trample the wicked, For they shall be ashes under the soles of your feet On the day that I do this,” Says the Lord of hosts.
In the new heaven-earth universe (Isaiah 65:17-22, 2 Peter 3:10-13, Revelation 21:1), the lake of fire bottomless pit will be the fiery core of that mammoth planet and the ashes of the doomed will actually be under the soles of the feet of the residents of the surface of the planet-heaven.