one is geography. the donor lungs can only be a few hours away or they simply will not last. two, size, adult lungs can be modified to fit sarah but they cannot be too big or they won't work and finally, blood type. it has to match. so the body will not reject it the bottom line here, shep, is the family needs the stars to align and they need them to align very quickly, shep? >> shepard: today, health experts held a big meeting on organ transplant rules for kids, trace. >> it led to it a big change, shep. you had lawyers arguing that the rule under 12 should be changed. you had a transplant patient saying that the real key is to get more donors involved, people to sign up. most of the doctors said the rules should not be changed because inherently it was not unfair. up about but then you had the chairman of the organ transplant who said kids under 12 should be taken case by case. listen to him. >> standard to allow centers to request a lung