My Senior class' slogan this year was "The World Ends With Us" and we used the Mayan calendar as a logo. I even have a t-shirt with that and all 500 of the class' names listed on it.
Also, some of you are misunderstanding how population growth works yet again. Overpopulation, as Criptfiend said, is not a thing that modernized countries have to worry about. Indeed, it is not something anyone outside of Africa has to worry about because the only countries that could realistically overshoot their carrying capacity, or already have, are in Africa.
Cultural attitudes towards families naturally shift from wanting large numbers of children to wanting small numbers of children or even to not wanting children at all as nations shift from agrarian to industrialized economies. This is well documented, and may well be an inevitable consequence of industrialization. Nutjob movements like Quiverfull are more of a drop in the ocean than an actual threat to societal views on numbers of children.
The number of living humans is not going to reach 20 billion any time soon. We would have to have large and established off-world societies for that to be even remotely possible. 10 billion at global ZPG (zero population growth) is the moderate estimate, 12 billion is the liberal estimate, 8 billion the conservative estimate. This is of course ruling out any multibillion strong human die-offs in the next 50 years, but that's not very likely.
Populations naturally even out. Freaking out about it and trying to mess with it through extreme policies doesn't solve anything. China tried that with the One-Child Policy. India tried to a lesser degree with their disaster of a sterilization campaign. Now there are 100 million fewer women in Asia than there actually should be and the region's population pyramid has gone lopsided. That's not going to make the population even out any quicker, and if anything it will increase the time it takes by making the region unstable. Marriage is very culturally important in India and China, but now there is literally a shortage of available women. Nothing good can come of that setup.
TL;DR: We're going to be fine, so calm down already.Modern Catholics are okay with it, like they are will pretty much everything. Obviously more traditional ones are not.
No idea which is more prevalent.
There was that thing the Pope did where he told everyone that condoms cause HIV. He's taken a less....insane stance about condoms in the past two years, but he's still the Pope either way.