As a heterosexual father of two boys about to enter my 60s who was raised in a Catholic family and went to mass weekly from probably the age of 5 to around 18 I have to say that Catholic teachings on sexual morality and human sexual behaviour leave me at best cold and more often revolted. There is nothing in my experience of sexual relationships that resonates with the those teachings at all.

Considering the subject of how to have a sustainable existence, do you think this approach might be effective? If not, why not?

The honest practice of regulation of birth demands first of all that husband and wife acquire and possess solid convictions concerning the true values of life and of the family, and that they tend towards securing perfect self-mastery. To dominate instinct by means of one's reason and free will undoubtedly requires ascetical practices, so that the affective manifestations of conjugal life may observe the correct order, in particular with regard to the observance of periodic continence. Yet this discipline which is proper to the purity of married couples, far from harming conjugal love, rather confers on it a higher human value. It demands continual effort yet, thanks to its beneficent influence, husband and wife fully develop their personalities, being enriched with spiritual values. Such discipline bestows upon family life fruits of serenity and peace, and facilitates the solution of other problems; it fosters attention for one's partner, helps both parties to drive out selfishness, the enemy of true love; and deepens their sense of responsibility. By its means, parents acquire the capacity of having a deeper and more efficacious influence in the education of their offspring: little children and youths grow up with a just appraisal of human values, and in the serene and harmonious development of their spiritual and sensitive faculties.

Quite possibly. What I heard at the time of the encyclical seemed sensible. We would disagree profoundly on birth control though.

It sounds like you are in agreement with Pope Francis, especially your edited short version. Have you read the encyclical?

Where are you getting your facts from?

Ah yes silly me. I like the fact that my children all survived birth and childhood. I guess I'm just selfish like that. Selfish enough I'd like everyones children to survive birth and childhood. I'll go and make an act of contrition and say 5 Hail Mary's. Will that remove my sin ? Or should I sacrifice a fatted calf or something ?

What overpopulation? By what standard do you declare that there are too many people? The only standard you can possibly use to declare that is the standard of the first world.

Of course, the planet could never support a large population based upon excessive first world consumption. Are you declaring that lavish first world consumption is the only way to live? Are you saying that the number of humans must be limited to a level where the planet can support them at first world standards?

Humans can live with far lower per capita resources than those consumed by the first world. Why should their numbers be limited to uphold an essentially wasteful and profligate way of life?

is a lone voice against the relentless march of global inequality.

Anything that the RCC says in opposition to the march of global inequality is sadly outweighed by the fact that it is, to a large extent, it is responsible for the over population. To suggest the RCC is a lone voice on this topic is laughable. I guess you don't read anything from the political left or from people who work in the development sector? You know the kind of people who try to see the world as it is without superstitious blinkers on.

The world has nowhere near the resources to bring the great bulk of humanity to the consumption levels of the first world.

But it's not just that. The hegemony of the first world is not underpinned by its excessive consumption or even its military power. These are symptoms of something more fundamental which is the fact that the first world owns and controls much of the wealth on the planet through its investments and financial products.

And since the first world's currencies are sound, it can print more and more money without significantly debasing them, creating even more wealth for itself. And since the planet's resources are finite, that means even less wealth for the remaining bulk of humanity.

The imbalance will only get worse, not better, in the future, as more and more wealth is concentrated into fewer and fewer hands. The Church faces challenging times in a world where the increasing concentration of wealth is systemic. She is a lone voice against the relentless march of global inequality.

I think 6 billion is too high. I would want a global population size that allows:

(a) an equal standard of living for everyone on the planet who wants it

(b) a standard of living at least as high as what we have now but also able to grow as time passes and technology advances

(c) sustainable long term use of resources. By long term I mean millennia, lots of millennia.

(d) recovery of the environment from its present degraded state including recovery from the dramatic species loss we are currently undergoing.

I don't know what the number is that would allow (a) - (d) but the suggestions I've seen are 1 - 2 billion. It's hard to calculate. But that's my problem with 6 billion.

EDIT: Short version. I don't care about the number of people as long as we can have (a) - (d).