Where did all the children go?

I just returned from 17 days in China.  Let me say first of all that the Chinese people could not have been kinder or more welcoming.  They love to practice their English on Americans since their government's policy makes it unlikely that they will be able to travel to America.  However, children do start to learn English from the very early grades and people do quite well considering the huge differences between English and Chinese.   We could learn something there.
Among other places, I visited the four largest cities in China.  China has 1.3 billion people- yep that's billion with a "B".   It has 1/4th of the world's population.  I mention this fact not because I want to show off what I learned but because of this next very curious experience.
In the seventeen days of my visit, including many standard tourist attractions, that were predominately frequented by Chinese not westerners, I saw not ONE, that is correct, not a single child with a disability.
My curiosity started with questions about how China does special education.   I was met with quizzical and confused looks.   Finally I was told that we do have some schools for deaf people.  I believe they do but I did not see a single person sign to another.  I was frequently asked to notice the strips of concrete tread engraved into sidewalks.  I was told that these were to help the blind.   But I never saw a single vision impaired person, no white canes, no guide dogs.
Then came the final question.  What about people with learning problems or emotional problems.  That was when the looks got really confused.  Often people just said "we don't have any".  Now granted with as many people as China has there are many jobs that can be managed with limited cognition.  For example, people sweep the curbs of major highways with brooms made of bamboo.  They wash down the road dividers with mop like hand tools.  Things are clean in China that Americans have no expectation of being clean or expect a machine to come along and do the job.
But the people doing these jobs looked just like everyone else.  We did not see a single person who was visibly disabled.  By contrast, on the relatively short hop from Chicago to the east coast on our return, there was a boy who looked to be about 12.   He also looked to be and acted as someone with autism.  Right there, right away, barely back in our country was a person with a disability.
Where are they in China?  Surely China must have its share of kids with disabling syndromes.   Here is what is scary.  China has a one child policy.  There are severe sanctions for failure to adhere, even to the extreme in some areas of forced abortion.  Are these children allowed to die at birth?  Are they given up for adoption?  China still has orphanages and still allows westerners to adopt out.
These children have to be born and they have to be somewhere- but where are they?