Children are cute but is childhood a social construct?

Ironic really, since today was the day I audited the Rights of the Child module. It was the end of the day and I was trying to convince some of my fellow LL.M. candidates to attend it with me.
I’m bored of child rights
Not really interested…
Okay, given that today’s class was just a brief history lesson, aren’t child’s rights supposed to be the fun part of human rights? The part where we can all legitimately get fired up and morally appalled at the horrific ways that children are treated around the world?
Because children do have a right to be protected. Because they are a vulnerable demographic. Because childhood is an innate part of your life that holds a special quality.
Well, perhaps not really.
The conception of childhood has always varied from culture to culture and even the modern western paradigm of today hasn’t come to a consensus as to when a child becomes an adult.
At 18, they can vote. At 15, they can live independently. At 19, they can drink. At 16, they can drive. At 12, they can be found criminally responsible.
The problem doesn’t end with the arbitrary numbers that we have forced on children as a way to questionably determine their physical, mental and emotional maturity, we have abstract ideas about what children are and how we perceive them in any case.
For instance, we separate children from adults, they play different games and wear different clothes. We have an idea of them as innocent and naive, incapable of doing harm. We know that children aren’t rational actors so we protect them from themselves by suspending some of their rights until they mature.
But what I found most interesting of all is how we bear the burden of this responsibility.
I keep finding the notion tied to bodily rights and freedom- why is it the duty of human beings to take care of and support other human beings (even if the latter human being is their offspring)?
John Locke extrapolates about the love and affection that a parent has for a child but he never goes so far as to deem it a duty, for isn’t “paternalism [an] odious tyranny” (Archer, 2004)? Of course, the main idea being that as much as children need guidance and guardianship, adults deserve their freedom just the same.
This is relevant in terms of what quite a few of my friends struggle with. They don’t want to have children and resent the society that inflicts parenthood upon them.
In the ideal world, I do want children. And, aside from the children’s rights aspect, I find myself mulling over the right of adults to not have children or to take any responsibility for any children at all.
Of course, this is a small part of the debate concerning the history of child rights but it’s a compelling one nonetheless.