When Muslims go to heaven, can they have children? If so that be ackward or abnormal because if they age they will eventually become older than their parents.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Allah Says about the pleasure of Paradise (what means): {And therein is whatever the souls desire and [what] delights the eyes, and you will abide therein eternally.} [Quran 43: 71]

Whatever a person desires when in Paradise, he gets it. He may desire to have children; Abu Sa’eed Al-Khudri narrated that the Prophet said: “When the believer desires to have a child in Paradise, this child's carriage, delivery, and his becoming young will be in only one hour just as the believer desires.” [Ibn Maajah]

Another narration by Ibn Hibban reads: "The delivery of this child and his becoming young as he wishes will last only one hour."

Abu Hurayrah reported that the Prophet said: “The people who enter Paradise enter it hairless, white colored and looking as if kohl was put in their eyes, thirty-three years old.” [Ahmad and At-Tirmithi]

The scholars disagreed on whether or not the person can have a child in Paradise and on whether or not women in Paradise deliver at all. Some of them said that there are children in Paradise based upon the previous Hadeeth. Others said that there are no children in Paradise because the Hadeeth does not say explicitly that the person gets the child. It actually stipulates a condition which is "if he desires" and he (the person in Paradise) does not desire this at all. This is what Is-haaq ibn Rahawayh narrated from Al-Bukhaari. Ahmad and Al-Haakim reported from Laqeet a Hadeeth in which it is narrated: “O Prophet of Allah! Do we have good pious wives in it (i.e. Paradise).” The Prophet said: “The pious wives are for the pious husbands. You get pleasure with them in Paradise as you used to get pleasure with them in this life, with one exception that there are no children.”

Besides, Abdur-Razzaaq reported that Abu Ad-Dardaa’ said: “There is neither sperm nor death in it. They (the men) have sexual intercourse as much as they can.”

Allah is the only One who knows what will happen to His Slaves then. What is proved by sound evidence is that whatever the dwellers of Paradise wish or desire they get it. But there is no evidence that they may wish to have children.

Allah knows best.