One of those wives is supposedly a daughter of weird Omar, leader of the Taleban. But Omar has only been married for about seven years, which would make his oldest daughter seven years old.
BTW, for an insight into Islamic sexuality, or what passes for it, try: "Unveiled" by Cherry Mosteshar.
In nations permitting polygamy, the rich and powerful are able to claim many of the available pool of eligible young virgin girls. This leave a large number of poor and powerless men with no chance of every finding a mate.
These nations must then be tyrannies, to prevent the powerless men from turning their anger and frustration against the rich and powerful who have taken so many females. In Islamic countries, the clerics may be counted in this group: Mullah Omar, the leader of the Talibans, is rich with many wives.
In order to prevent the anger of the unmarried from turning against these regimes, they must focus the anger on outside targets: in this case they blame the West for all of their ills.
If the above is true, I believe that bin Laden may be feeling sexually repressed right now.