One child, extremely intelligent, chatty, wise for their years beyond belief. Wins awards for something they are so talented in and is unusual for their age.
Another child completely and utterly disabled in every way possible, cannot even understand their own name at the age of 6. Will never lead a normal life. Autistic, severe learning difficulties, multiple disorders. Gets halfway through primary school and still can't talk or use the toilet.
Same father. No disabilities either side of the family. You meet a new man and fall pregnant. Would you keep the baby? Or be afraid of it inheriting similar disabilities as the second child?