Being asexual, I prefer that my video games pretend that sex doesn't exist.
However, besides that, I don't think it'd be a good addition to the game. Having young children would add no value. While you might get benefits from having an heir (e.g. Right to rule) you would need to care for that child, which would be negative for gameplay, or if you ignored childcare it would be weird and affect the suspension of disbelief. Children aging at a normal pace is impractical, children aging rapidly would affect the suspension of disbelief.
All in all, a lot of work for something that wouldn't improve the game, in my opinion.