Hi!  My daughter was diagnosed with 3 kidneys as an infant.  She has 3 fully functioning kidneys and ureters!  She has one normal sized kidney on the left and one normal size kidney on the right with a smaller one about it on the right.  The urologist says that 1 in 4 people have 1, 3, or 4 kidneys...so it is more common than you think.  But most people don't know unless they need an ultrasound for something!  My daughter had kidney infections, but not because she had three kidneys, but because she had grade 2 and 3 reflux on the two kidneys on the right.  She took prophylactic doses of anitbiotics for several years to prevent infections, but eventually the condition corrected itself and she has healthy kidneys.  Surgery would have been an option if it didn't correct itself!

So she is 12 now...and has had no issues whatsoever!