Many online websites some written by doctors are saying boys stop growing taller at 16, true or false ?

Generally: Generally true though not always. After onset of puberty, growth plates of long bones begin to close, and when completely sealed, there can be no more growth in stature. Later onset puberty may lead to taller final height. Some boys keep growing and some have late spurts, but most boys, by age of 16-17 can no longer gain height.

Depends: The chronological age is sometimes ignored by the body.Genetics often drives the outcome of growth and influences when puberty starts and ends.Linear growth is possible as long as the growth centers of the long bones remain open.The hormones of puberty drive both the growth spurt and a signal to close the growth centers. This occurs by age 16-17 in most males, but can linger to 20 or so.