The test can rule out for DS but you could still end up with a child who has disabilities that can’t be picked up on any scan or test. Autism for example. They could develop a childhood illness like meningitis and develop a disability. If you truly don’t want to raise a child/adult with a disability then the only way to guarantee it is to not have children. Ever. It’s hard work having disabled children (I have 2) but it doesn’t mean you love them any less. You’ve probably just really upset her, so please talk to her, tell her how strong you think she is and tell her you just wouldn’t be strong enough to raise a child with additional needs. Tell her how amazing you think she is for being that mum. Apologise for any upset you caused - because while you didn’t mean to upset her you’d still apologise for hurting somebody by accident. And this is one of those times. She’s your grandma, why would you want her upset with you especially when she’s grieving? While her raising your aunt might have looked like hell to you I can assure you it was love, it was joyous, it was her world poured into raising her. Her daughter was her everything, the same as your mum is her everything, and she’s just lost her. It doesn’t matter that she had Downs. Your gran loved her. She raised her, she fought for her, she birthed her. And now she’s lost her. And you’ve hurt her. Go make it up to her.