Yeah, I've never been able to understand this dynamic, which seems to be true all over the world.
Well, I can't speak for the whole world, but I can explain the Chinese situation better. Keep in mind, for most of China's history, China operated on a feudal system, where the peasant class (who represented the vast majority of the nation's population) received little or no actual money for their work. Instead, their 'lord' would provide them with housing, food, etc., in return for their work. In this system, "wealth" manifested itself in the size of one's family -- the more people you had, the more work the family could do, and (usually) the more your lord rewarded you.
In addition, there were pretty much no options for health care, retirement, etc. The Chinese feudal system's version of an RRSP was "have as many kids as you can"...cuz they're the ones who are going to take care of you and provide for you when you get older. Again, the more kids you have, the more resources there are for them to take care of you when you're old.
Even in terms of education...feudal China
did have a system of state exams where someone from a peasant background could gain higher positions within the government, and thereby enrich their family. But again, the cost of educating a child to prepare for those exams was rarely taken on by the peasant family...it was taken on by their lord, who would sponsor the child's education and training in return for an expectation of being favored if the child reached higher positions later in life. But this was possible
only if the family already had lots of children, so that sponsoring one of the kids wouldn't have an adverse affect on the family's overall productivity.
Thus, Chinese cultural values surrounding families are mired in thousands of years of history, based on a feudal system where children were literally the main form of "wealth" available to the majority of the population.
China's change to a market-style economy turned all of that on its head. Now, more children means
less wealth. But among a great deal of the peasant population in China, they don't understand that. They are still bound by values handed down by their parents, grandparents, great-grandparents, etc....values that teach that "more children" is equal to "more wealth" and "more opportunity".
The problem with the debate about the one-child policy is that it is inevitably framed in terms of human rights -- but the "human rights" we are talking about are actually in direct opposition to each other.
On the one hand, we have the "rights" of parents to be able to choose for themselves how many children they want to have. On the other hand, we have the "rights" of children to be given the best opportunities. Removing the one-child policy focuses on the former rights; enforcing restrictions on how many children families (or more specifically, peasant families) can have focuses on the latter.
I will admit to personally leaning towards the latter option. Because "violating" a person's right to have as many children as they want will, hopefully, lead to a situation where subsequent generations will have
more money and opportunity, and therefore bring an end to the cycle of poverty; whereas letting them have as many kids as they want means that the cycle remains in place, and subsequent generations of children will face exactly the same problems.
Like many situations in China, this isn't one where there's a "good choice" and a "bad choice". There are only several "bad choices", and you have to choose which one is least bad. In this case, I'd advocate that the main factor in determining what policy to follow isn't how it affects
this generation...but what impact it will have on
subsequent generations. The policy that will most greatly improve the situation of later generations is the best one; the policy that is most likely to leave later generations in the same or worse situation is the worst.