I just received a newsletter by a, now (it was once a fringe group but has become more influential) group known as Negative Population Growth [npg.org] Their latest newsletter was titled "In praise of population decline" and was about how changing world circumstances are driving a lower fertility rates globally. Here is a portion of that newsletter

"The phenomenon is best explained as an ecological response that naturally sets in for a population when that species’ population is nearing the limits of its habitat’s carrying capacity. The pressures of the limits to growth aren’t necessarily what’s causing it; rather, a species’ tendency to see its members cluster together as a resource acquisition and sharing strategy increases that species’ average population density. This then amplifies the stress factors that individuals in that population must deal with. In these more crowded conditions, the “cost of living” for individuals increases. It takes more time and effort to acquire resources competitively. It becomes more difficult to find available or adequate nesting grounds. Organisms tend to cluster together because this makes life easier initially, but eventually, the crowding becomes too much and life becomes more difficult instead – something works until it doesn’t work anymore. As population density increases, these stress factors compel those individuals, both behaviorally and biologically, to give birth to fewer offspring in an effort to alleviate this stress. Ecologists call this density dependence, and this force has been found to influence population dynamics for nearly all organisms on Earth. There is an expanding body of evidence that shows density dependence – simply put, rising population density – is the force behind globally collapsing birth rates. That is the ecological reason for falling birth rates."
"Here are the sociological explanations: stress, fear, and anxiety about the future.
It is true that science, philosophy, reason and the modern popular consensus on morals and human rights, often disagree with the teachings of religion. But it is also true, that even where they do agree with religious teaching, they often provide far stronger proofs for those points of agreement. Which in at least, one way that is actually perhaps even more important than the disagreements.
In this world that we live in, where humans exist in service to the economy, those humans are working longer and harder for this “growth first and foremost” model economy, and for far less pay when weighed against inflation. Their cost of living – especially housing – soars and soars with each passing year, especially in jurisdictions where population expansion is outstripping home construction, as it always does and always will. This is what’s occurring in Canada today, and it’s been happening in the United States for some time now. Competition for employment, especially for the good-paying kind, is so fierce that people fear the sudden loss of jobs and income. People are anxious about the future and their ability to afford a home, let alone raise a family in one without having to worry about catastrophic future unemployment. And the larger and more crowded the city, the stronger this anxiety and stress becomes; and the lower the birth rate goes.
This is the reality that the economists’ growth- first model has delivered. It is the very cause of the global birth rate collapse. The forces driving reproduction lower are doing so because there is only one possible direction the future human population can sustainably go: down. The “growth first at all costs and consequences” model is coming to an end."

I think the larger and more established the group the more they become like a tribe.

@pedigojr I think it’s far simpler than that…the higher the proportion of educated women there are in a society the lower the birth rates are. That is for a variety of reasons…educated women want to work and have a career first, then they are pickier about choosing a partner looking for one who is at least an intellectual equal, they want to make sure of financial security before procreating so wait until it’s financially viable. Many decide that actually their career is more fulfilling than having children and decide not to bother with having a family at all, and others leave it too late to conceive because their biological clocks have run out. Educated women are less likely to pay attention to religious diktats too, so all in all education is the key to a lower birth rate and to a lower tolerance to religious dogma.

@Marionville That works in a developed country but most of the time women in undeveloped countries don't have a choice or sometimes even know that such options, as birth control even exist. In many counties even birth control is illegal (and maybe even here if SCROTUS gets a chance to change the law). I have been using that term as our Supreme Court still has 3 (women) who are sane and vote as true justices. It was said after some of the horrible decisions by the others these 3 go into a room to cry. There needs to be a separation between the sane group and the activists ones. Supreme Court Republicans of the US. The name fits for those 6 Justices.

@pedigojr I’m aware of that which is why my original reply stated that “Religion is the major stumbling block to sensible birth control policies…especially in predominantly Catholic and Muslim countries “. It is why Theocracies and other countries where religious dictat forbids or discourages contraception, also quite often prevent education of girls and ban women from working after marriage. Education is the key to women having fewer children, education is the key to women being independent and making decisions about birth control. That cannot be allowed in religious, misogynistic societies, that is why we need to put the conditions of universal education for girls, and the education and supply of contraceptive methods to women in developing countries as a condition to receiving Western aid.

@Marionville Sorry, it's been a while since I responded but some issues with my property forced me to put my energies elsewhere. This is becoming a common issue among many of us of a 'certain age' in that property maintenance has become too much and we need to look at a more viable life change.
I agree with you comments but also realize there are often more at stake. As I said in my original comment what's going on now applies to all life forms. "The phenomenon is best explained as an ecological response that naturally sets in for a population when that species’ population is nearing the limits of its habitat’s carrying capacity. The pressures of the limits to growth aren’t necessarily what’s causing it; rather, a species’ tendency to see its members cluster together as a resource acquisition and sharing strategy increases that species’ average population density." The global human population growth rate is falling and it is the constant growth based economic system that is in panic and trying to reverse the trend. Religion is often used as a weapon but so are other tactics. In thins country the attempt to outlaw abortion was seen as a way to increase our numbers but the reverse is happening. It is not a simple situation.

By educating them AND letting them have more control over their bodies. The global birth rate is going down but the major source of population growth is from people fleeing their country's that have been ravaged by environmental ills and moving to developed countries. It is the developed countries that have the biggest environmental impact and are the most in need of population reduction.

It's true but they can plant a few seeds and, now it seems, this issue has been around a long time.