If a child is born with certain weakness or disability whose fault it is?

Agreed, I don't think it's anyone's fault. It is just science — you don't know which gene of which parent is being passed on to the kid. Our society usually blames mothers for any weakness the child might have. Either the mom didn't eat well during pregnancy or she ate too much or exercised too much, slept in a particular position or didn't sit well. Oh, too many! It's time we brush these stigmas aside and accept our children as they are. If there is a disability, instead of playing the blame game, we should focus on providing a nurturing environment to the child.