Doctors here are confounded by the medical condition of Abhishek, all of five years and seven months but with physical characteristics like a moustache, beard and deep voice of an adult man.
The boy's face gives the impression of a grown man in his mid-20s and his reproductive organs too have developed like that of an adult.
Abhishek, born in November 2000, is the third son of Pramod Kumar of Choti Balia, a village in Begusarai district, about 130 km from here, in the eastern Indian state of Bihar.
A worried Kumar has consulted dozens of doctors from Begusarai to Patna in the last few years but was repeatedly told that he would have to take his son for medical tests outside Bihar.
"At first all the doctors were surprised to see my son as for them he was a rare medical case," Kumar, a schoolteacher, told IANS.
"Doctors have suggested that I take him (Abhishek) to the Sanjay Gandhi Institute of Medical Sciences in Lucknow. But my financial condition does not permit me to take him there," he said.
According to Kumar, Abhishek was a normal, healthy child at the time of birth. But slowly his growth became abnormal.
"Abhishek's voice turned deep like an adult's when he was merely one-and-a-half years old," said Kumar.
Vipin Kumar, a paediatrician who examined Abhishek, said the balance of hormones in his endocrine glands was not normal.
The endocrine glands secrete hormones that regulate body functions like metabolism, growth and development, and reproduction.
"The sex hormone that is usually produced by the body around the age of 18 years is already being secreted in his body," said the doctor.
While Abhishek's physically growth is like that of an adult, his mental development remains that of a child.
"He is like other children of his age. He pronounces many words like a child and does other things like children," his father said.
Abhishek was first admitted to the Indira Gandhi Institute of Medical Sciences here for treatment on the advice of doctors. But after months of expensive treatment, he was taken home.
"There was no benefit despite the costly treatment," said Kumar.
Early this week, Abhishek was brought to Sadar hospital in Begusarai for a check up.
"At first, doctors were surprised to know that he was less than six-years-old as he appeared to be an adult. A three-member medical board examined him," said Gopal Mishra, one of doctors who carried out Abhishek's check-up.
His medical report will be submitted to the hospital this week after some tests.