Hello , while donating one kidney , you are doing a wonderful humanitarian work which people do rarely. The other kidney takes over all the work and you have to maintain a good dietary control life long . If everything remains good in control no need to worry . If you don't have Hypertension, DIABETES or other chronic illnesses or risk factors , you can donate safely. But since you have a sickle cell trait , do consult with a hematologist as well, since that's not my field