... In theory there could be events that provide you with wives, or the sovereign could produce a child magically because... well... he's a channeler, he can do whatever he wants.
Hmm. That functionality should enable a truly all-female Amazon Faction, in combination with the 'pop growth comes from the wilderness' thing and possible corrollary 'fertilization magic' for the general population.
Frankly, though, I'll be pleased and surprised if the devs plan for Life magic to include things like spawning offspring from thighs or foreheads. It'd be really neat to be a kingdom faction with strong Life magic and try to 'do the Fallen right.' Bet that'd piss some empire folks off but good...