How tall can you be without suffering any health risks or problems like the tumor in the pituitary gland. what affects height?

No definite number: A person who develops a pituitary tumor after adolescent growth has stopped (around age 18 usually) will not grow taller, but will develop a change in the shape of his face, diabetes, visual trouble, etc. (This is called acromegaly.) If such a tumor occurs before growth has stopped, gigantism can result. A 34 year old person, simply unusually tall and not symptomatic, not likely have tumor.