[user104658]

The "natural" age of weaning (when a child would choose to stop themselves without encouragement) can be anywhere between 2 and about 8. It would be perfectly normal for "wild humans" to still be having breastmilk aged 6. Really, it's society and society's expectations that are "weird"... And also I suspect that people who see a child of any age breastfeeding and make a sexual connection are the ones who have subconscious psychosexual issues - not the one doing the breastfeeding. It is the observer making that link who is sexualising children.

As for where this problem comes from, I think it's the tendency to push children to "grow up" ever more quickly. The workload my daughter has in early primary school aged just 5, is MUCH more than when I was that age. The goal of our lovely capitalist way of life is to have parents back in work ASAP, and have kids away from their parents learning to be effective workers ASAP... So our perspective is skewed and we look at children as being older than they are.

A lot of the time my 5 year old speaks and acts indistinguishably from a teenager. But then at other times there are moments when it strikes me that she really is still just a baby.