I can't believe a) that this thread has been reignited and b) that I am contributing again!
Some things have caught me though. On the lactose intolerance stuff, here's what wikipedia says:
Most mammals normally become lactose intolerant when they are young; however, some human populations have developed lactase persistence, where lactase production continues into adulthood. It is estimated that 75% of adults worldwide show some decrease in lactase activity during adulthood.[2] The frequency of decreased lactase activity ranges from as little as 5% in northern Europe, up to 71% for Sicily, to more than 90% in some African and Asian countries.
Maybe that is why these other cultures bf for longer?
Or maybe those of us domesticating animals and using them have had lactase ability selected for or perhaps in these other countries there are other environmental reasons why babies bf are better suited that doesn't apply in Europe. Without doing a bunch of cladistics it's chicken and egg in a debate like this. NB. The 'most' humans argument is not really quite relevant given that China has 1/6-1/7 of the world's population alone.
This debate about normal bothers me too as I think the concept is just not being interpreted right. Normal means most common, it's a statistical measure. Norms change based on how the sample changes. What is normal in the UK is to not bf an 8 year old, what might be normal in some particular African culture might be to wean at 5 years old (I don't recall seeing a post here with evidence that it is normal anywhere to bf at 8 years). Normal doesn't mean right or wrong, in fact nothing means right or wrong except the values individuals place on something. Here I think most people are not loving the bf at 8 years old. It's definitely not normal, but that doesn't make it wrong.
I am totally in favour of bf, both mine were/are bf and I don't ever use formula. I am in complete agreement that it is nutritionally best suited for our babies/toddlers but I think that it is probably the case that the prevalence of bf links to the availability of nutritional food and potentially the local racial genetics in relation to foods containing the required vitamins. What's natural is for people to do what meets their needs to maximise survival of their offspring, which may or may not be bf well into childhood.
I'd be interested to see how the weaning age data relates to position of the child in the family. Are mums more likely to wean one child when another comes along if otherwise left to their own devices? There are likely to be many subtleties to the real data rather than some average. Perhaps youngest children tend to bf the longest.
Putting aside that sometimes 'evidence' for one argument or another irritates me, I couldn't care less what someone else does!
It's the parental prerogative to do what we feel is best and there are many ways to mess up our children and they are in many ways surprisingly resilient to our mistakes. Maybe these children will go up on the social fringes cast out for their unusual ways, or maybe they will grow up to extend bf their children, or neither and maybe it won't really make any difference either way. Who's to say?