The neonatal kidney achieves concentrating ability equivalent to adult's kidney by:
One year of age
Eighteen months of age
Three to six months of age
Just before pubey
Answer is A (One year of age) : "Normal adult kidney can produce urine with an osmolalitv of greater than 1000 m Osm/kg water. The healthy new born infant, subject to water deprivation for 10-14 hours can achieve an osmolality of only 500-700 m osm / kg. This value increases gradually during the first few months and approximates to the adult value by about one year of age."