Gord

You need to collect 4 artifacts "image of a woman". It gives +10% to the birth rate in the settlement. Then we build 4 meaderies, upgrade them, send all subjects to the meaderies. Wait a couple of minutes and voila!!
Oh, yes, we distribute women's artifacts to adult women; it doesn't work for older women, I've checked!
I looked for artifacts from traveling merchants, their inventory is updated over time!