@Lazarou sometimes its worse than that and they *do* sacrifice their own children (I noticed this when studying military history of WW2 and its linked to the "full quiver" thing the Christian theocrats do where they force their wives to have as many kids as possible as they know they are going to lose a few fighting their "holy wars" (although reality in USA is its just due to lack of healthcare, too many guns and poor attitudes to road safety)
There is a risk that govts are more devious and don't directly introduce conscription (the Council of Europe discourages it) but create economic situations where its more attractive for lower income youths to sign up as all the entry level jobs they would othewise get are gone..