Hi all , i came across this site after thinking i have 3.5 kidneys ( duplex kidney syndrome is inherent in our family , my mother had one kidney 3 times its normal size but it never worked . I had a mild teenage kidney infection when 13 and was given an iodine xray , that's when they discovered tat one of my kidney was 2.5 times its normal size . some people get 4 kidneys with Duplex .