The question that you ask is very informed and also very complex. If you opt for a cadaver kidney transplant, your waiting time is likely to be very long, depending on the kidney center where you are listed. The living related donor with 100% matching HLA antigens, is most likely to be successful, but sometimes transplanting small kidneys from women into larger men does not supply them with enough kidney tissue to maintain long term function. Your sister will be left with lower kidney function as well but this is commonly sufficient for a smaller female. I do not believe I can offer an opinion, but you should discuss your concerns with your transplant nephrologist, who knows your history and current medical status. It is best for you to think this problem through with someone who knows you and your medical history.