Ok, this is half humorous and half serious. But I'd wager that the answer is non-zero.
This is all just anecdotal, obviously, but I think childless humans with pet indoor dogs could have less of a desire to procreate for various reasons, but perhaps mainly because the instinctual thirst to care for a living thing is quinched to some extent when you have a pet indoor dog.
Obviously not every or most or even many. But perhaps _some_.
It's not entirely surprising that both of these world champions saw that as a way to keep the game interesting.
Something else that Magnus sometimes does, even against fellow grandmasters, is play a completely ridiculous opening that's obviously bad. But more importantly, it's different, and all the existing opening theory goes out the window.
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As it was, our pre-marriage relationship was a period of huge growth for both of us until marriage was a natural progression, by which time we were both very different people but better suited to one another. When we had kids our relationship was strong and it got use through some tough times. It's a long road but it's a more stable one.
So no, no regrets.