"Natural" ... yes.
It's the instinct to perpetuate the species.
But it is, of course, a "primitive" instinct. We still have many primitive instincts.
Some of our primitive instincts are still useful ... the "fight or flight" instinct whereby a rush of adrenalin increases our reaction times in dangerous situations.
Some are not useful ... the instinct to consume carbohydrates, even though they taste bland, because our bodies are telling us to store fuel for when our hunting trips are unsuccessful (that's why we love chips, by the way).
Some of them are largely irrelevant ... our heart rate slows down if we put our faces in cold water (yes, really!)
I'd say the "perpetuate the species" instinct falls into the category of "irrelevant" in a society where the species is hardly likely to die out.
Nevertheless ... the instinct does still exist.