I don't think the one-child policy would make people crazy or any less strange. The only downside would be if the couple wanted a son to carry the surname but end up having a daughter instead of a son, they may be disappointed enough to give the child up for adopt and try again. Whether the law in China allows that, I have no idea…..China must have their reasons for adopting a one-child policy, but we, in the western world may see this policy as cruel or extreme but do bare in mind, China has more people (billions) then any other countries combined. The most spoken language in the world is Mandarin but I’m guessing with billions of people alone, this would push the language into first place and placing English as the second most spoken language in the world.
Not sure about mentally, but there are definitely problems surrounding the policy. Girl babies are often beaten to death in the mother's womb as soon as it is established that the unborn child is to be a girl. Babies are found in dumpsters and down storm drains as the couple do not want a girl, because a boy is more sought after (can carry on the family name, and boys are seen as fighters that provide for the family). It is becoming a problem now as the new generation in china is very, very heavily tilted on the young men side, with copious amounts of little boys, and a very limited amount of girls.
To be honest, girls are often just left to die when they're born because so many families do want girls. Another problem with the policy is that there's a whole network of people kidnapping baby boys and selling them to other families.
A few years back I saw a documentary that said there is a mojor problem in China now because of this policy. There is a huge deficit of Chinese women available for all these male children, now grown men. to marry.