The Bible indicates in Zechariah 13:8 that one third of the Jews living in Israel will survive the Apocalypse, which is about 2,000,000 people.
Presently there are about 6 million Jews living in Israel, and one third is therefore 2,000,000 people left over. If we assume that one family is made up of a husband and wife with two children, and if we assume that 50% are male. God has planned for these survivors to be the good seed beginning the millennial nation of Israel. But we also have these verses to consider:
And seven women shall take hold of one man in that day, saying, “We will eat our own bread, and wear our own apparel: only let us be called by thy name; take thou away our reproach.” In that day shall the branch of Jehovah be beautiful and glorious, and the fruit of the land shall be excellent and comely for them that are escaped of Israel.
And it shall come to pass, that he that is left in Zion , and he that remained in Jerusalem, shall be called holy , even every one that is written among the living in Jerusalem; when the Lord shall have washed away the filth of the daughters of Zion, and shall have purged the blood of Jerusalem from the midst thereof, by the spirit of justice, and by the spirit of burning.
And Jehovah will create over the whole habitation of mount Zion, and over her assemblies, a cloud and smoke by day, and the shining of a flaming fire by night; for over all the glory [shall be spread] a covering. And there shall be a pavilion for a shade in the day-time from the heat, and for a refuge and for a covert from storm and from rain. (Isaiah 4:1-5 ASV)
In Isaiah 3, we are introduced to the Apocalypse time seeing the second mountain peak looking through a distant prophetic telescope. So the next chapter says that there will be 7 women to one man ratio. Most men will have been killed in the conflict, so women and children will predominant among the survivors.
In Revelation 7:4, 144,000 men are sealed for a special purpose. They are upright, believers, and morally untainted from the corrupt system. God identifies them and elects them to survive the Apocalypse. So we apply the 1:7 ratio by multiplying 144,000 men x 7 women = 1,008,000 people. Since we have assumed a mean average where the number of children equals the number of adults, then 1 million children can be added to reach the 2 million figure, being one third of the 6 million Jews living in Israel today. The 144,000 sealed men and 7 women ratio will be the startup population mix of the restored nation of Israel. They will be given a special honor as the founding citizens of the New World Order.
We should not make too many assumptions about family structure from this analysis. Also, the initial 2 million population will be increased with migrations of scattered Israelites back to the promised land during the early months of the millennium. (Isaiah 11 and others)