btw, there are conditions that you can test for but can only test for v late.
DD2 and I were squeezed (only just, they had to lower the table) into an MRI chamber to try to detect whether she had one of DD1's conditions. At 34 weeks. They said they just couldn't tell any earlier. There was a strong assumption if they had detected it, that I should terminate, just a few weeks before term and definitely at a viable age.
As it goes, I wouldn't have, but my point is really it does happen like that with some detectable brain abnormalities, even the very serious ones (this is one where 70% of affected kids have half their brain removed in infancy so I think it counts as fairly serious). It's not just a question of feckless teenagers not fancying a baby with an extra toe or something.
I don't know if that affects what I think about the Cameron quotes - I just mean the "it's easy to lower it to 24 weeks because obviously if it's serious you'll know by then" argument is incorrect.