duplex kideny

I have just found out in the 21 weeks scan my fetus (boy) has a left duplex kidney, in the uters there is a ballon where the urine flues. currently it seems normal with the rine flues, doctor said I should be scaned every three weeks. Can you please say more about this condition, some Q: I understand there will be an operation needed to remove one kidney, does it mean the other kidney will get back to its normal size. do you have a specialised doctor to recommend in israel? Many thanks

I cannot answer without seeing exactly how it looks. The best thing is to be examined in a hospital unit including consultation with a pediatric nephrologist.