Couldn't have anything to do with Putin giving respect and priority to the Orthodox Christian Church, could it? Nah. Never mind.
Russia appears to get it right while America continues to get it wrong. I honestly would prefer having Putin as my president. Sigh.
Is it because religiously observant people don't use contraception and don't abort? Or is it because people of faith are consciously glorifying and pleasing God with more citizens for the Kingdom? Or is it that the "kind" of people who are devout (a temperament thing) tend also to be the "kind" of people who get satisfaction from having a goodly crop of kids?
Just guessing here.
Or maybe people who trust in God are more likely to say "Another kid? NOw? Well, OK, [calming their incipient panic] God will provide, somehow."
I personally --- as you know --- didn't seem to have much maternal "instinct" nor natural attraction to babies, until I was well into my 30's. I just had never had contact with babies. They seemed like soft-serv space aliens to me. But the baby-hunger came on me pretty robustly once we got married. And actually, I had a strong feeling, "Don-o ought to be a father. May his tribe increase!"
So, for me, anyhow, that was how and why.