When people complain about the environmental impact of larger families, why is the impact of starting a family young not mentioned?

[CuppaTeaJanice]

Sorry thay's a bit of a long thread title! But I've seen a lot of articles over the years about large families (ie. lots of children in the same generation) being a drain on the planet's resources, and nothing about the impact of families who tend to have children young.

For example, take two hypothetical women - Sarah Smith and Jenny Jones.

Sarah Smith has 3 children on her 20th birthday, and these 3 children each have 3 children of their own on their 20th birthdays and so on (I realise that this is very over-simplified).

Jenny Jones has 3 children on her 30th birthday, and these 3 children have their own 3 children on their 30th birthdays etc.

120 years after her own birth, Sarah Smith has produced a staggering 1092 descendants!

Jenny Jones has only 120 descendants.

In fact, if Jenny and her offspring had each had 4 children there would only be 340 descendants, and 5 children each makes 780 - still significantly less people (and less environmental impact) than the Smith family.

If the Jones family had had their children at the age of 40 they could have had 9 children each and still produce less descendants than the Smiths.

Nothing wrong with having children young of course. I just thought it was interesting that it never gets brought up in population/environment discussions.

Because young mothers get blamed for enough - from society's ills, to drug culture, to child illiteracy levels, to dropping marriage statistics, to rises in housing benefit payments, to childhood obesity.

let's not make them carry the planet too.

Mainly because you can't make assumptions over so many generations.
My mum had us quite old and I am the youngest. I had my children relatively young. When I look at my childrens peers grandparents they are generally around the same age as my parents. Of course you will get exceptions but it just shows its not as simple as all that.

Anyway I may have scarred my children so much they all choose to have one or no children each.

Too many factors

I'm not trying to put blame onto anybody Colditz, I just think it's interesting that a lot of people seem to limit the numbers of children they have due to environmental concerns regarding an increasing population. I've never heard of anybody planning to have children later to spread the generations out for the same reason, although from my OP it seems this has more influence, numbers-wise.

Bronze, I know it's over-simplifying things and there are huge numbers of exceptions, but in my experience a lot of people look at their parents lifestyles and life choices as inspiration for their own, and this includes age of procreation. I know families with five generations alive because they all have children quite young, and other families where the third generation is quite elderly when their grandchildren are born. I guess it only takes one or two generations to go against the norm and even things out again though!!

But if you wait 10/20 years, wouldn't it all even out? (SOrry, I might be beign thick here, trying to MN during teatime rush!)

but is it not that subsequent generations have less children on the whole. certainly . i've less children than my parents and grandparents.. only one less, but that will have an impact surely? my sister has also had one less and my brother has no children yet.

i really don't think you can rationalise or extrapolate it as simplistically.

most people i know have had less children than their parents and grandparents

it's all a load of bollocks anyway IMO. Say all the environmentally concious people only had one child, and all of the people who couldn't care less about the planet had loads of children, and all those people passed on their values to their children.

Next generation the proportion of environmentally concious people would be far lower than it is now and the world would still be fucked because even more people would be being wasteful and careless!

also, i had my first child at a younger age than my mum had us. my sister had her first child 7 years after i had my first.