- US, British and Australian birth rates for teen and young adults were flat in the earliest years of this century but fell markedly from 2007

- The same slide occurred in France and Poland in 2009, and in Mexico , Morocco and Indonesia from 2012

- In Ghana, Nigeria and Senegal, fertility had been declining, but the fall became precipitous 2013-2015

All of these inflection points coincide with the mass adoption of smartphones in the respective countries, as measured by Google searches for mobile apps. The younger the preponderant age group in a given country, the more pronounced the downturn. 

There is then a debate on whether this effect could be caused by either there being less time spent on person-to-person socialising, or whether smartphone images raise expectations in choosing a partner to an unattainable degree.

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Having a "wank bank" in the pocket for men is part of it, I would suggest, but there's so much more. I've said before, but for the UK (and indeed much of the West), look at the way many if not most of the Boomers were able to raise a family on a single income, with the mum staying at home to raise the children, the dad's job paying off the mortgage single-handedly, and no need for childcare. Compare that with today, where you need two incomes, and thus would need childcare, and in the meantime rents are through the roof, there are next to no council houses etc, etc. 

Personally I feel the world is overpopulated and I decided as a teenager to not have children, as I could see the plague of humans crawling across the dusty, heat-seared land in decades to come... it's sort of come true, too, in that we now have many thousands more houses in the borough than we did in the 90s, and indeed most summers are now dusty and cracked! I certainly wouldn't want to bring a child into this world, watching things get steadily worse over the past couple of decades and knowing that climate change looms large - it's very depressing, frankly!

Others will have different reasons, my friends for example have seen relationships in their family and friends break down and want no part of that themselves. I've never wanted a partner so am happy alone - there will be others like me.

Falling populations are, IMO, an excellent thing, and rather than whinge about it (as some are wont to do) we need to embrace it; there will be a gnarly part as the Boomers die off (as they're such a large cohort), but get that out the way and things will get easier. And as I've said before, look to countries like Japan in how to deal with it.

EDIT: And the overall reason for declining populations is simply that as living standards (in terms of being able to be fed and having basic healthcare) improve globally, there's less need to have swarms of children in the hope that one or two survive. Even in the 90s, at school, the population charts in my geography textbook showed a fall in pretty much all countries by the end of this century, a few in Africa excepted - it's not a new phenomenon and was well forecast IMO.

I think that the point of the report was that there had been a much sharper decline once smartphones became available, on top of the general decline to which you refer.

Nevertheless, there was a fair amount of 'post hoc, ergo propter hoc' in the conclusions reached. But I found the idea intriguing and so worth sharing.

Agree with much of that, though porn is probably not relevant.  Masturbation has been going on since we were living in caves! However, I do think most men  have a  genetic instinct to pass on their genes.  Why do men hate condoms so much, not just because of the reduced pleasure, but because it goes against natural instinct to inseminate when presented with a vagina.