I'm ok donating one of my organs as long as I have two of them.
If I were to donate any of my organs, it would have to be an organ that I have more than one of.
ーI'm ok donating one of my organs as long as I have two of them.
「複数ある臓器なら、その一つを提供しても良い。」
donate「寄付する・提供する」
organ「臓器」
as long as「〜するかぎり」
have two of them を使って「複数ある臓器」を表現しました。
ーIf I were to donate any of my organs, it would have to be an organ that I have more than one of.
「もし臓器を提供するなら、複数ある臓器でなければならない。」
have more than one of でも「複数ある臓器」を表現できます。
ご参考まで！
カナダ 
