I am a father myself in Frankfurt, Germany, where we have one of the highest relative number of children compared to the rest of the (rather childless) country.
As someone else mentioned, we are also getting better at treating disabilities in children through better healthcare and parental nutrition. Cerebral Palsy, for example, can be congenital where something happens to the child in the womb or acquired through brain injury as a child, both of these can be prevented (or likelihood reduced significantly) with better medical care, there is also genetic predisposition which cannot be prevented (currently) by modern medicine. So it doesnt mean all children with cerebral palsy (and this is a very apparent/visual disability) are being aborted, it may mean we are better at preventing it occurring in the first place.
Spina bifada is prevented by ensuring that the mother has enough folic acid. I have an uncle with Spina Bifada (he is in his late 60's now) but it is so easily preventable in first world nations (folic acid is readily available as a supplement) that it is likely due to better healthcare and not abortion.
There are so many other changes in healthcare attitudes such as knowing that drinking alcohol/smoking while pregnant is not healthy and can impact on the unborn child that we take for granted, but 50 years ago they prescribed guinness to expectant mothers because of its supposed high iron content.
TO assume it is all down to aborting unhealthy children is to deny the advances that we have made with modern healthcare.
